diff --git a/gl/base64.c b/gl/base64.c
new file mode 100644
index 00000000..f0754612
--- /dev/null
+++ b/gl/base64.c
@@ -0,0 +1,605 @@
+/* base64.c -- Encode binary data using printable characters.
+   Copyright (C) 1999-2001, 2004-2006, 2009-2014 Free Software Foundation, Inc.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU Lesser General Public License as published by
+   the Free Software Foundation; either version 2.1, or (at your option)
+   any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public License
+   along with this program; if not, see <http://www.gnu.org/licenses/>.  */
+
+/* Written by Simon Josefsson.  Partially adapted from GNU MailUtils
+ * (mailbox/filter_trans.c, as of 2004-11-28).  Improved by review
+ * from Paul Eggert, Bruno Haible, and Stepan Kasal.
+ *
+ * See also RFC 4648 <http://www.ietf.org/rfc/rfc4648.txt>.
+ *
+ * Be careful with error checking.  Here is how you would typically
+ * use these functions:
+ *
+ * bool ok = base64_decode_alloc (in, inlen, &out, &outlen);
+ * if (!ok)
+ *   FAIL: input was not valid base64
+ * if (out == NULL)
+ *   FAIL: memory allocation error
+ * OK: data in OUT/OUTLEN
+ *
+ * size_t outlen = base64_encode_alloc (in, inlen, &out);
+ * if (out == NULL && outlen == 0 && inlen != 0)
+ *   FAIL: input too long
+ * if (out == NULL)
+ *   FAIL: memory allocation error
+ * OK: data in OUT/OUTLEN.
+ *
+ */
+
+#include <config.h>
+
+/* Get prototype. */
+#include "base64.h"
+
+/* Get malloc. */
+#include <stdlib.h>
+
+/* Get UCHAR_MAX. */
+#include <limits.h>
+
+#include <string.h>
+
+/* C89 compliant way to cast 'char' to 'unsigned char'. */
+static unsigned char
+to_uchar (char ch)
+{
+  return ch;
+}
+
+static const char b64c[64] =
+  "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
+
+/* Base64 encode IN array of size INLEN into OUT array. OUT needs
+   to be of length >= BASE64_LENGTH(INLEN), and INLEN needs to be
+   a multiple of 3.  */
+static void
+base64_encode_fast (const char *restrict in, size_t inlen, char *restrict out)
+{
+  while (inlen)
+    {
+      *out++ = b64c[to_uchar (in[0]) >> 2];
+      *out++ = b64c[((to_uchar (in[0]) << 4) + (to_uchar (in[1]) >> 4)) & 0x3f];
+      *out++ = b64c[((to_uchar (in[1]) << 2) + (to_uchar (in[2]) >> 6)) & 0x3f];
+      *out++ = b64c[to_uchar (in[2]) & 0x3f];
+
+      inlen -= 3;
+      in += 3;
+    }
+}
+
+/* Base64 encode IN array of size INLEN into OUT array of size OUTLEN.
+   If OUTLEN is less than BASE64_LENGTH(INLEN), write as many bytes as
+   possible.  If OUTLEN is larger than BASE64_LENGTH(INLEN), also zero
+   terminate the output buffer. */
+void
+base64_encode (const char *restrict in, size_t inlen,
+               char *restrict out, size_t outlen)
+{
+  /* Note this outlen constraint can be enforced at compile time.
+     I.E. that the output buffer is exactly large enough to hold
+     the encoded inlen bytes.  The inlen constraints (of corresponding
+     to outlen, and being a multiple of 3) can change at runtime
+     at the end of input.  However the common case when reading
+     large inputs is to have both constraints satisfied, so we depend
+     on both in base_encode_fast().  */
+  if (outlen % 4 == 0 && inlen == outlen / 4 * 3)
+    {
+      base64_encode_fast (in, inlen, out);
+      return;
+    }
+
+  while (inlen && outlen)
+    {
+      *out++ = b64c[to_uchar (in[0]) >> 2];
+      if (!--outlen)
+        break;
+      *out++ = b64c[((to_uchar (in[0]) << 4)
+                       + (--inlen ? to_uchar (in[1]) >> 4 : 0))
+                      & 0x3f];
+      if (!--outlen)
+        break;
+      *out++ =
+        (inlen
+         ? b64c[((to_uchar (in[1]) << 2)
+                   + (--inlen ? to_uchar (in[2]) >> 6 : 0))
+                  & 0x3f]
+         : '=');
+      if (!--outlen)
+        break;
+      *out++ = inlen ? b64c[to_uchar (in[2]) & 0x3f] : '=';
+      if (!--outlen)
+        break;
+      if (inlen)
+        inlen--;
+      if (inlen)
+        in += 3;
+    }
+
+  if (outlen)
+    *out = '\0';
+}
+
+/* Allocate a buffer and store zero terminated base64 encoded data
+   from array IN of size INLEN, returning BASE64_LENGTH(INLEN), i.e.,
+   the length of the encoded data, excluding the terminating zero.  On
+   return, the OUT variable will hold a pointer to newly allocated
+   memory that must be deallocated by the caller.  If output string
+   length would overflow, 0 is returned and OUT is set to NULL.  If
+   memory allocation failed, OUT is set to NULL, and the return value
+   indicates length of the requested memory block, i.e.,
+   BASE64_LENGTH(inlen) + 1. */
+size_t
+base64_encode_alloc (const char *in, size_t inlen, char **out)
+{
+  size_t outlen = 1 + BASE64_LENGTH (inlen);
+
+  /* Check for overflow in outlen computation.
+   *
+   * If there is no overflow, outlen >= inlen.
+   *
+   * If the operation (inlen + 2) overflows then it yields at most +1, so
+   * outlen is 0.
+   *
+   * If the multiplication overflows, we lose at least half of the
+   * correct value, so the result is < ((inlen + 2) / 3) * 2, which is
+   * less than (inlen + 2) * 0.66667, which is less than inlen as soon as
+   * (inlen > 4).
+   */
+  if (inlen > outlen)
+    {
+      *out = NULL;
+      return 0;
+    }
+
+  *out = malloc (outlen);
+  if (!*out)
+    return outlen;
+
+  base64_encode (in, inlen, *out, outlen);
+
+  return outlen - 1;
+}
+
+/* With this approach this file works independent of the charset used
+   (think EBCDIC).  However, it does assume that the characters in the
+   Base64 alphabet (A-Za-z0-9+/) are encoded in 0..255.  POSIX
+   1003.1-2001 require that char and unsigned char are 8-bit
+   quantities, though, taking care of that problem.  But this may be a
+   potential problem on non-POSIX C99 platforms.
+
+   IBM C V6 for AIX mishandles "#define B64(x) ...'x'...", so use "_"
+   as the formal parameter rather than "x".  */
+#define B64(_)                                  \
+  ((_) == 'A' ? 0                               \
+   : (_) == 'B' ? 1                             \
+   : (_) == 'C' ? 2                             \
+   : (_) == 'D' ? 3                             \
+   : (_) == 'E' ? 4                             \
+   : (_) == 'F' ? 5                             \
+   : (_) == 'G' ? 6                             \
+   : (_) == 'H' ? 7                             \
+   : (_) == 'I' ? 8                             \
+   : (_) == 'J' ? 9                             \
+   : (_) == 'K' ? 10                            \
+   : (_) == 'L' ? 11                            \
+   : (_) == 'M' ? 12                            \
+   : (_) == 'N' ? 13                            \
+   : (_) == 'O' ? 14                            \
+   : (_) == 'P' ? 15                            \
+   : (_) == 'Q' ? 16                            \
+   : (_) == 'R' ? 17                            \
+   : (_) == 'S' ? 18                            \
+   : (_) == 'T' ? 19                            \
+   : (_) == 'U' ? 20                            \
+   : (_) == 'V' ? 21                            \
+   : (_) == 'W' ? 22                            \
+   : (_) == 'X' ? 23                            \
+   : (_) == 'Y' ? 24                            \
+   : (_) == 'Z' ? 25                            \
+   : (_) == 'a' ? 26                            \
+   : (_) == 'b' ? 27                            \
+   : (_) == 'c' ? 28                            \
+   : (_) == 'd' ? 29                            \
+   : (_) == 'e' ? 30                            \
+   : (_) == 'f' ? 31                            \
+   : (_) == 'g' ? 32                            \
+   : (_) == 'h' ? 33                            \
+   : (_) == 'i' ? 34                            \
+   : (_) == 'j' ? 35                            \
+   : (_) == 'k' ? 36                            \
+   : (_) == 'l' ? 37                            \
+   : (_) == 'm' ? 38                            \
+   : (_) == 'n' ? 39                            \
+   : (_) == 'o' ? 40                            \
+   : (_) == 'p' ? 41                            \
+   : (_) == 'q' ? 42                            \
+   : (_) == 'r' ? 43                            \
+   : (_) == 's' ? 44                            \
+   : (_) == 't' ? 45                            \
+   : (_) == 'u' ? 46                            \
+   : (_) == 'v' ? 47                            \
+   : (_) == 'w' ? 48                            \
+   : (_) == 'x' ? 49                            \
+   : (_) == 'y' ? 50                            \
+   : (_) == 'z' ? 51                            \
+   : (_) == '0' ? 52                            \
+   : (_) == '1' ? 53                            \
+   : (_) == '2' ? 54                            \
+   : (_) == '3' ? 55                            \
+   : (_) == '4' ? 56                            \
+   : (_) == '5' ? 57                            \
+   : (_) == '6' ? 58                            \
+   : (_) == '7' ? 59                            \
+   : (_) == '8' ? 60                            \
+   : (_) == '9' ? 61                            \
+   : (_) == '+' ? 62                            \
+   : (_) == '/' ? 63                            \
+   : -1)
+
+static const signed char b64[0x100] = {
+  B64 (0), B64 (1), B64 (2), B64 (3),
+  B64 (4), B64 (5), B64 (6), B64 (7),
+  B64 (8), B64 (9), B64 (10), B64 (11),
+  B64 (12), B64 (13), B64 (14), B64 (15),
+  B64 (16), B64 (17), B64 (18), B64 (19),
+  B64 (20), B64 (21), B64 (22), B64 (23),
+  B64 (24), B64 (25), B64 (26), B64 (27),
+  B64 (28), B64 (29), B64 (30), B64 (31),
+  B64 (32), B64 (33), B64 (34), B64 (35),
+  B64 (36), B64 (37), B64 (38), B64 (39),
+  B64 (40), B64 (41), B64 (42), B64 (43),
+  B64 (44), B64 (45), B64 (46), B64 (47),
+  B64 (48), B64 (49), B64 (50), B64 (51),
+  B64 (52), B64 (53), B64 (54), B64 (55),
+  B64 (56), B64 (57), B64 (58), B64 (59),
+  B64 (60), B64 (61), B64 (62), B64 (63),
+  B64 (64), B64 (65), B64 (66), B64 (67),
+  B64 (68), B64 (69), B64 (70), B64 (71),
+  B64 (72), B64 (73), B64 (74), B64 (75),
+  B64 (76), B64 (77), B64 (78), B64 (79),
+  B64 (80), B64 (81), B64 (82), B64 (83),
+  B64 (84), B64 (85), B64 (86), B64 (87),
+  B64 (88), B64 (89), B64 (90), B64 (91),
+  B64 (92), B64 (93), B64 (94), B64 (95),
+  B64 (96), B64 (97), B64 (98), B64 (99),
+  B64 (100), B64 (101), B64 (102), B64 (103),
+  B64 (104), B64 (105), B64 (106), B64 (107),
+  B64 (108), B64 (109), B64 (110), B64 (111),
+  B64 (112), B64 (113), B64 (114), B64 (115),
+  B64 (116), B64 (117), B64 (118), B64 (119),
+  B64 (120), B64 (121), B64 (122), B64 (123),
+  B64 (124), B64 (125), B64 (126), B64 (127),
+  B64 (128), B64 (129), B64 (130), B64 (131),
+  B64 (132), B64 (133), B64 (134), B64 (135),
+  B64 (136), B64 (137), B64 (138), B64 (139),
+  B64 (140), B64 (141), B64 (142), B64 (143),
+  B64 (144), B64 (145), B64 (146), B64 (147),
+  B64 (148), B64 (149), B64 (150), B64 (151),
+  B64 (152), B64 (153), B64 (154), B64 (155),
+  B64 (156), B64 (157), B64 (158), B64 (159),
+  B64 (160), B64 (161), B64 (162), B64 (163),
+  B64 (164), B64 (165), B64 (166), B64 (167),
+  B64 (168), B64 (169), B64 (170), B64 (171),
+  B64 (172), B64 (173), B64 (174), B64 (175),
+  B64 (176), B64 (177), B64 (178), B64 (179),
+  B64 (180), B64 (181), B64 (182), B64 (183),
+  B64 (184), B64 (185), B64 (186), B64 (187),
+  B64 (188), B64 (189), B64 (190), B64 (191),
+  B64 (192), B64 (193), B64 (194), B64 (195),
+  B64 (196), B64 (197), B64 (198), B64 (199),
+  B64 (200), B64 (201), B64 (202), B64 (203),
+  B64 (204), B64 (205), B64 (206), B64 (207),
+  B64 (208), B64 (209), B64 (210), B64 (211),
+  B64 (212), B64 (213), B64 (214), B64 (215),
+  B64 (216), B64 (217), B64 (218), B64 (219),
+  B64 (220), B64 (221), B64 (222), B64 (223),
+  B64 (224), B64 (225), B64 (226), B64 (227),
+  B64 (228), B64 (229), B64 (230), B64 (231),
+  B64 (232), B64 (233), B64 (234), B64 (235),
+  B64 (236), B64 (237), B64 (238), B64 (239),
+  B64 (240), B64 (241), B64 (242), B64 (243),
+  B64 (244), B64 (245), B64 (246), B64 (247),
+  B64 (248), B64 (249), B64 (250), B64 (251),
+  B64 (252), B64 (253), B64 (254), B64 (255)
+};
+
+#if UCHAR_MAX == 255
+# define uchar_in_range(c) true
+#else
+# define uchar_in_range(c) ((c) <= 255)
+#endif
+
+/* Return true if CH is a character from the Base64 alphabet, and
+   false otherwise.  Note that '=' is padding and not considered to be
+   part of the alphabet.  */
+bool
+isbase64 (char ch)
+{
+  return uchar_in_range (to_uchar (ch)) && 0 <= b64[to_uchar (ch)];
+}
+
+/* Initialize decode-context buffer, CTX.  */
+void
+base64_decode_ctx_init (struct base64_decode_context *ctx)
+{
+  ctx->i = 0;
+}
+
+/* If CTX->i is 0 or 4, there are four or more bytes in [*IN..IN_END), and
+   none of those four is a newline, then return *IN.  Otherwise, copy up to
+   4 - CTX->i non-newline bytes from that range into CTX->buf, starting at
+   index CTX->i and setting CTX->i to reflect the number of bytes copied,
+   and return CTX->buf.  In either case, advance *IN to point to the byte
+   after the last one processed, and set *N_NON_NEWLINE to the number of
+   verified non-newline bytes accessible through the returned pointer.  */
+static char *
+get_4 (struct base64_decode_context *ctx,
+       char const *restrict *in, char const *restrict in_end,
+       size_t *n_non_newline)
+{
+  if (ctx->i == 4)
+    ctx->i = 0;
+
+  if (ctx->i == 0)
+    {
+      char const *t = *in;
+      if (4 <= in_end - *in && memchr (t, '\n', 4) == NULL)
+        {
+          /* This is the common case: no newline.  */
+          *in += 4;
+          *n_non_newline = 4;
+          return (char *) t;
+        }
+    }
+
+  {
+    /* Copy non-newline bytes into BUF.  */
+    char const *p = *in;
+    while (p < in_end)
+      {
+        char c = *p++;
+        if (c != '\n')
+          {
+            ctx->buf[ctx->i++] = c;
+            if (ctx->i == 4)
+              break;
+          }
+      }
+
+    *in = p;
+    *n_non_newline = ctx->i;
+    return ctx->buf;
+  }
+}
+
+#define return_false                            \
+  do                                            \
+    {                                           \
+      *outp = out;                              \
+      return false;                             \
+    }                                           \
+  while (false)
+
+/* Decode up to four bytes of base64-encoded data, IN, of length INLEN
+   into the output buffer, *OUT, of size *OUTLEN bytes.  Return true if
+   decoding is successful, false otherwise.  If *OUTLEN is too small,
+   as many bytes as possible are written to *OUT.  On return, advance
+   *OUT to point to the byte after the last one written, and decrement
+   *OUTLEN to reflect the number of bytes remaining in *OUT.  */
+static bool
+decode_4 (char const *restrict in, size_t inlen,
+          char *restrict *outp, size_t *outleft)
+{
+  char *out = *outp;
+  if (inlen < 2)
+    return false;
+
+  if (!isbase64 (in[0]) || !isbase64 (in[1]))
+    return false;
+
+  if (*outleft)
+    {
+      *out++ = ((b64[to_uchar (in[0])] << 2)
+                | (b64[to_uchar (in[1])] >> 4));
+      --*outleft;
+    }
+
+  if (inlen == 2)
+    return_false;
+
+  if (in[2] == '=')
+    {
+      if (inlen != 4)
+        return_false;
+
+      if (in[3] != '=')
+        return_false;
+    }
+  else
+    {
+      if (!isbase64 (in[2]))
+        return_false;
+
+      if (*outleft)
+        {
+          *out++ = (((b64[to_uchar (in[1])] << 4) & 0xf0)
+                    | (b64[to_uchar (in[2])] >> 2));
+          --*outleft;
+        }
+
+      if (inlen == 3)
+        return_false;
+
+      if (in[3] == '=')
+        {
+          if (inlen != 4)
+            return_false;
+        }
+      else
+        {
+          if (!isbase64 (in[3]))
+            return_false;
+
+          if (*outleft)
+            {
+              *out++ = (((b64[to_uchar (in[2])] << 6) & 0xc0)
+                        | b64[to_uchar (in[3])]);
+              --*outleft;
+            }
+        }
+    }
+
+  *outp = out;
+  return true;
+}
+
+/* Decode base64-encoded input array IN of length INLEN to output array
+   OUT that can hold *OUTLEN bytes.  The input data may be interspersed
+   with newlines.  Return true if decoding was successful, i.e. if the
+   input was valid base64 data, false otherwise.  If *OUTLEN is too
+   small, as many bytes as possible will be written to OUT.  On return,
+   *OUTLEN holds the length of decoded bytes in OUT.  Note that as soon
+   as any non-alphabet, non-newline character is encountered, decoding
+   is stopped and false is returned.  If INLEN is zero, then process
+   only whatever data is stored in CTX.
+
+   Initially, CTX must have been initialized via base64_decode_ctx_init.
+   Subsequent calls to this function must reuse whatever state is recorded
+   in that buffer.  It is necessary for when a quadruple of base64 input
+   bytes spans two input buffers.
+
+   If CTX is NULL then newlines are treated as garbage and the input
+   buffer is processed as a unit.  */
+
+bool
+base64_decode_ctx (struct base64_decode_context *ctx,
+                   const char *restrict in, size_t inlen,
+                   char *restrict out, size_t *outlen)
+{
+  size_t outleft = *outlen;
+  bool ignore_newlines = ctx != NULL;
+  bool flush_ctx = false;
+  unsigned int ctx_i = 0;
+
+  if (ignore_newlines)
+    {
+      ctx_i = ctx->i;
+      flush_ctx = inlen == 0;
+    }
+
+
+  while (true)
+    {
+      size_t outleft_save = outleft;
+      if (ctx_i == 0 && !flush_ctx)
+        {
+          while (true)
+            {
+              /* Save a copy of outleft, in case we need to re-parse this
+                 block of four bytes.  */
+              outleft_save = outleft;
+              if (!decode_4 (in, inlen, &out, &outleft))
+                break;
+
+              in += 4;
+              inlen -= 4;
+            }
+        }
+
+      if (inlen == 0 && !flush_ctx)
+        break;
+
+      /* Handle the common case of 72-byte wrapped lines.
+         This also handles any other multiple-of-4-byte wrapping.  */
+      if (inlen && *in == '\n' && ignore_newlines)
+        {
+          ++in;
+          --inlen;
+          continue;
+        }
+
+      /* Restore OUT and OUTLEFT.  */
+      out -= outleft_save - outleft;
+      outleft = outleft_save;
+
+      {
+        char const *in_end = in + inlen;
+        char const *non_nl;
+
+        if (ignore_newlines)
+          non_nl = get_4 (ctx, &in, in_end, &inlen);
+        else
+          non_nl = in;  /* Might have nl in this case. */
+
+        /* If the input is empty or consists solely of newlines (0 non-newlines),
+           then we're done.  Likewise if there are fewer than 4 bytes when not
+           flushing context and not treating newlines as garbage.  */
+        if (inlen == 0 || (inlen < 4 && !flush_ctx && ignore_newlines))
+          {
+            inlen = 0;
+            break;
+          }
+        if (!decode_4 (non_nl, inlen, &out, &outleft))
+          break;
+
+        inlen = in_end - in;
+      }
+    }
+
+  *outlen -= outleft;
+
+  return inlen == 0;
+}
+
+/* Allocate an output buffer in *OUT, and decode the base64 encoded
+   data stored in IN of size INLEN to the *OUT buffer.  On return, the
+   size of the decoded data is stored in *OUTLEN.  OUTLEN may be NULL,
+   if the caller is not interested in the decoded length.  *OUT may be
+   NULL to indicate an out of memory error, in which case *OUTLEN
+   contains the size of the memory block needed.  The function returns
+   true on successful decoding and memory allocation errors.  (Use the
+   *OUT and *OUTLEN parameters to differentiate between successful
+   decoding and memory error.)  The function returns false if the
+   input was invalid, in which case *OUT is NULL and *OUTLEN is
+   undefined. */
+bool
+base64_decode_alloc_ctx (struct base64_decode_context *ctx,
+                         const char *in, size_t inlen, char **out,
+                         size_t *outlen)
+{
+  /* This may allocate a few bytes too many, depending on input,
+     but it's not worth the extra CPU time to compute the exact size.
+     The exact size is 3 * (inlen + (ctx ? ctx->i : 0)) / 4, minus 1 if the
+     input ends with "=" and minus another 1 if the input ends with "==".
+     Dividing before multiplying avoids the possibility of overflow.  */
+  size_t needlen = 3 * (inlen / 4) + 3;
+
+  *out = malloc (needlen);
+  if (!*out)
+    return true;
+
+  if (!base64_decode_ctx (ctx, in, inlen, *out, &needlen))
+    {
+      free (*out);
+      *out = NULL;
+      return false;
+    }
+
+  if (outlen)
+    *outlen = needlen;
+
+  return true;
+}
diff --git a/gl/base64.h b/gl/base64.h
new file mode 100644
index 00000000..9b636c65
--- /dev/null
+++ b/gl/base64.h
@@ -0,0 +1,68 @@
+/* base64.h -- Encode binary data using printable characters.
+   Copyright (C) 2004-2006, 2009-2014 Free Software Foundation, Inc.
+   Written by Simon Josefsson.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU Lesser General Public License as published by
+   the Free Software Foundation; either version 2.1, or (at your option)
+   any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public License
+   along with this program; if not, see <http://www.gnu.org/licenses/>.  */
+
+#ifndef BASE64_H
+# define BASE64_H
+
+/* Get size_t. */
+# include <stddef.h>
+
+/* Get bool. */
+# include <stdbool.h>
+
+# ifdef __cplusplus
+extern "C" {
+# endif
+
+/* This uses that the expression (n+(k-1))/k means the smallest
+   integer >= n/k, i.e., the ceiling of n/k.  */
+# define BASE64_LENGTH(inlen) ((((inlen) + 2) / 3) * 4)
+
+struct base64_decode_context
+{
+  unsigned int i;
+  char buf[4];
+};
+
+extern bool isbase64 (char ch) _GL_ATTRIBUTE_CONST;
+
+extern void base64_encode (const char *restrict in, size_t inlen,
+                           char *restrict out, size_t outlen);
+
+extern size_t base64_encode_alloc (const char *in, size_t inlen, char **out);
+
+extern void base64_decode_ctx_init (struct base64_decode_context *ctx);
+
+extern bool base64_decode_ctx (struct base64_decode_context *ctx,
+                               const char *restrict in, size_t inlen,
+                               char *restrict out, size_t *outlen);
+
+extern bool base64_decode_alloc_ctx (struct base64_decode_context *ctx,
+                                     const char *in, size_t inlen,
+                                     char **out, size_t *outlen);
+
+#define base64_decode(in, inlen, out, outlen) \
+        base64_decode_ctx (NULL, in, inlen, out, outlen)
+
+#define base64_decode_alloc(in, inlen, out, outlen) \
+        base64_decode_alloc_ctx (NULL, in, inlen, out, outlen)
+
+# ifdef __cplusplus
+}
+# endif
+
+#endif /* BASE64_H */
diff --git a/gl/gettimeofday.c b/gl/gettimeofday.c
new file mode 100644
index 00000000..88c6e4d6
--- /dev/null
+++ b/gl/gettimeofday.c
@@ -0,0 +1,154 @@
+/* Provide gettimeofday for systems that don't have it or for which it's broken.
+
+   Copyright (C) 2001-2003, 2005-2007, 2009-2014 Free Software Foundation, Inc.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU Lesser General Public License as published by
+   the Free Software Foundation; either version 2.1, or (at your option)
+   any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public License
+   along with this program; if not, see <http://www.gnu.org/licenses/>.  */
+
+/* written by Jim Meyering */
+
+#include <config.h>
+
+/* Specification.  */
+#include <sys/time.h>
+
+#include <time.h>
+
+#if HAVE_SYS_TIMEB_H
+# include <sys/timeb.h>
+#endif
+
+#if GETTIMEOFDAY_CLOBBERS_LOCALTIME || TZSET_CLOBBERS_LOCALTIME
+
+/* Work around the bug in some systems whereby gettimeofday clobbers
+   the static buffer that localtime uses for its return value.  The
+   gettimeofday function from Mac OS X 10.0.4 (i.e., Darwin 1.3.7) has
+   this problem.  The tzset replacement is necessary for at least
+   Solaris 2.5, 2.5.1, and 2.6.  */
+
+static struct tm tm_zero_buffer;
+static struct tm *localtime_buffer_addr = &tm_zero_buffer;
+
+# undef localtime
+extern struct tm *localtime (time_t const *);
+
+# undef gmtime
+extern struct tm *gmtime (time_t const *);
+
+/* This is a wrapper for localtime.  It is used only on systems for which
+   gettimeofday clobbers the static buffer used for localtime's result.
+
+   On the first call, record the address of the static buffer that
+   localtime uses for its result.  */
+
+struct tm *
+rpl_localtime (time_t const *timep)
+{
+  struct tm *tm = localtime (timep);
+
+  if (localtime_buffer_addr == &tm_zero_buffer)
+    localtime_buffer_addr = tm;
+
+  return tm;
+}
+
+/* Same as above, since gmtime and localtime use the same buffer.  */
+struct tm *
+rpl_gmtime (time_t const *timep)
+{
+  struct tm *tm = gmtime (timep);
+
+  if (localtime_buffer_addr == &tm_zero_buffer)
+    localtime_buffer_addr = tm;
+
+  return tm;
+}
+
+#endif /* GETTIMEOFDAY_CLOBBERS_LOCALTIME || TZSET_CLOBBERS_LOCALTIME */
+
+#if TZSET_CLOBBERS_LOCALTIME
+
+# undef tzset
+extern void tzset (void);
+
+/* This is a wrapper for tzset, for systems on which tzset may clobber
+   the static buffer used for localtime's result.  */
+void
+rpl_tzset (void)
+{
+  /* Save and restore the contents of the buffer used for localtime's
+     result around the call to tzset.  */
+  struct tm save = *localtime_buffer_addr;
+  tzset ();
+  *localtime_buffer_addr = save;
+}
+#endif
+
+/* This is a wrapper for gettimeofday.  It is used only on systems
+   that lack this function, or whose implementation of this function
+   causes problems.  */
+
+int
+gettimeofday (struct timeval *restrict tv, void *restrict tz)
+{
+#undef gettimeofday
+#if HAVE_GETTIMEOFDAY
+# if GETTIMEOFDAY_CLOBBERS_LOCALTIME
+  /* Save and restore the contents of the buffer used for localtime's
+     result around the call to gettimeofday.  */
+  struct tm save = *localtime_buffer_addr;
+# endif
+
+# if defined timeval /* 'struct timeval' overridden by gnulib?  */
+#  undef timeval
+  struct timeval otv;
+  int result = gettimeofday (&otv, (struct timezone *) tz);
+  if (result == 0)
+    {
+      tv->tv_sec = otv.tv_sec;
+      tv->tv_usec = otv.tv_usec;
+    }
+# else
+  int result = gettimeofday (tv, (struct timezone *) tz);
+# endif
+
+# if GETTIMEOFDAY_CLOBBERS_LOCALTIME
+  *localtime_buffer_addr = save;
+# endif
+
+  return result;
+
+#else
+
+# if HAVE__FTIME
+
+  struct _timeb timebuf;
+  _ftime (&timebuf);
+  tv->tv_sec = timebuf.time;
+  tv->tv_usec = timebuf.millitm * 1000;
+
+# else
+
+#  if !defined OK_TO_USE_1S_CLOCK
+#   error "Only 1-second nominal clock resolution found.  Is that intended?" \
+          "If so, compile with the -DOK_TO_USE_1S_CLOCK option."
+#  endif
+  tv->tv_sec = time (NULL);
+  tv->tv_usec = 0;
+
+# endif
+
+  return 0;
+
+#endif
+}
diff --git a/gl/m4/absolute-header.m4 b/gl/m4/absolute-header.m4
new file mode 100644
index 00000000..ce3e39e9
--- /dev/null
+++ b/gl/m4/absolute-header.m4
@@ -0,0 +1,102 @@
+# absolute-header.m4 serial 16
+dnl Copyright (C) 2006-2014 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl From Derek Price.
+
+# gl_ABSOLUTE_HEADER(HEADER1 HEADER2 ...)
+# ---------------------------------------
+# Find the absolute name of a header file, testing first if the header exists.
+# If the header were sys/inttypes.h, this macro would define
+# ABSOLUTE_SYS_INTTYPES_H to the '""' quoted absolute name of sys/inttypes.h
+# in config.h
+# (e.g. '#define ABSOLUTE_SYS_INTTYPES_H "///usr/include/sys/inttypes.h"').
+# The three "///" are to pacify Sun C 5.8, which otherwise would say
+# "warning: #include of /usr/include/... may be non-portable".
+# Use '""', not '<>', so that the /// cannot be confused with a C99 comment.
+# Note: This macro assumes that the header file is not empty after
+# preprocessing, i.e. it does not only define preprocessor macros but also
+# provides some type/enum definitions or function/variable declarations.
+AC_DEFUN([gl_ABSOLUTE_HEADER],
+[AC_REQUIRE([AC_CANONICAL_HOST])
+AC_LANG_PREPROC_REQUIRE()dnl
+dnl FIXME: gl_absolute_header and ac_header_exists must be used unquoted
+dnl until we can assume autoconf 2.64 or newer.
+m4_foreach_w([gl_HEADER_NAME], [$1],
+  [AS_VAR_PUSHDEF([gl_absolute_header],
+                  [gl_cv_absolute_]m4_defn([gl_HEADER_NAME]))dnl
+  AC_CACHE_CHECK([absolute name of <]m4_defn([gl_HEADER_NAME])[>],
+    m4_defn([gl_absolute_header]),
+    [AS_VAR_PUSHDEF([ac_header_exists],
+                    [ac_cv_header_]m4_defn([gl_HEADER_NAME]))dnl
+    AC_CHECK_HEADERS_ONCE(m4_defn([gl_HEADER_NAME]))dnl
+    if test AS_VAR_GET(ac_header_exists) = yes; then
+      gl_ABSOLUTE_HEADER_ONE(m4_defn([gl_HEADER_NAME]))
+    fi
+    AS_VAR_POPDEF([ac_header_exists])dnl
+    ])dnl
+  AC_DEFINE_UNQUOTED(AS_TR_CPP([ABSOLUTE_]m4_defn([gl_HEADER_NAME])),
+                     ["AS_VAR_GET(gl_absolute_header)"],
+                     [Define this to an absolute name of <]m4_defn([gl_HEADER_NAME])[>.])
+  AS_VAR_POPDEF([gl_absolute_header])dnl
+])dnl
+])# gl_ABSOLUTE_HEADER
+
+# gl_ABSOLUTE_HEADER_ONE(HEADER)
+# ------------------------------
+# Like gl_ABSOLUTE_HEADER, except that:
+#   - it assumes that the header exists,
+#   - it uses the current CPPFLAGS,
+#   - it does not cache the result,
+#   - it is silent.
+AC_DEFUN([gl_ABSOLUTE_HEADER_ONE],
+[
+  AC_REQUIRE([AC_CANONICAL_HOST])
+  AC_LANG_CONFTEST([AC_LANG_SOURCE([[#include <]]m4_dquote([$1])[[>]])])
+  dnl AIX "xlc -E" and "cc -E" omit #line directives for header files
+  dnl that contain only a #include of other header files and no
+  dnl non-comment tokens of their own. This leads to a failure to
+  dnl detect the absolute name of <dirent.h>, <signal.h>, <poll.h>
+  dnl and others. The workaround is to force preservation of comments
+  dnl through option -C. This ensures all necessary #line directives
+  dnl are present. GCC supports option -C as well.
+  case "$host_os" in
+    aix*) gl_absname_cpp="$ac_cpp -C" ;;
+    *)    gl_absname_cpp="$ac_cpp" ;;
+  esac
+changequote(,)
+  case "$host_os" in
+    mingw*)
+      dnl For the sake of native Windows compilers (excluding gcc),
+      dnl treat backslash as a directory separator, like /.
+      dnl Actually, these compilers use a double-backslash as
+      dnl directory separator, inside the
+      dnl   # line "filename"
+      dnl directives.
+      gl_dirsep_regex='[/\\]'
+      ;;
+    *)
+      gl_dirsep_regex='\/'
+      ;;
+  esac
+  dnl A sed expression that turns a string into a basic regular
+  dnl expression, for use within "/.../".
+  gl_make_literal_regex_sed='s,[]$^\\.*/[],\\&,g'
+  gl_header_literal_regex=`echo '$1' \
+                           | sed -e "$gl_make_literal_regex_sed"`
+  gl_absolute_header_sed="/${gl_dirsep_regex}${gl_header_literal_regex}/"'{
+      s/.*"\(.*'"${gl_dirsep_regex}${gl_header_literal_regex}"'\)".*/\1/
+      s|^/[^/]|//&|
+      p
+      q
+    }'
+changequote([,])
+  dnl eval is necessary to expand gl_absname_cpp.
+  dnl Ultrix and Pyramid sh refuse to redirect output of eval,
+  dnl so use subshell.
+  AS_VAR_SET([gl_cv_absolute_]AS_TR_SH([[$1]]),
+[`(eval "$gl_absname_cpp conftest.$ac_ext") 2>&AS_MESSAGE_LOG_FD |
+  sed -n "$gl_absolute_header_sed"`])
+])
diff --git a/gl/m4/base64.m4 b/gl/m4/base64.m4
new file mode 100644
index 00000000..9559e30b
--- /dev/null
+++ b/gl/m4/base64.m4
@@ -0,0 +1,15 @@
+# base64.m4 serial 4
+dnl Copyright (C) 2004, 2006, 2009-2014 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_BASE64],
+[
+  gl_PREREQ_BASE64
+])
+
+# Prerequisites of lib/base64.c.
+AC_DEFUN([gl_PREREQ_BASE64], [
+  AC_REQUIRE([AC_C_RESTRICT])
+])
diff --git a/gl/m4/gettimeofday.m4 b/gl/m4/gettimeofday.m4
new file mode 100644
index 00000000..1c2d66ee
--- /dev/null
+++ b/gl/m4/gettimeofday.m4
@@ -0,0 +1,138 @@
+# serial 21
+
+# Copyright (C) 2001-2003, 2005, 2007, 2009-2014 Free Software Foundation, Inc.
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+dnl From Jim Meyering.
+
+AC_DEFUN([gl_FUNC_GETTIMEOFDAY],
+[
+  AC_REQUIRE([AC_C_RESTRICT])
+  AC_REQUIRE([gl_HEADER_SYS_TIME_H])
+  AC_REQUIRE([gl_HEADER_SYS_TIME_H_DEFAULTS])
+  AC_CHECK_FUNCS_ONCE([gettimeofday])
+
+  gl_gettimeofday_timezone=void
+  if test $ac_cv_func_gettimeofday != yes; then
+    HAVE_GETTIMEOFDAY=0
+  else
+    gl_FUNC_GETTIMEOFDAY_CLOBBER
+    AC_CACHE_CHECK([for gettimeofday with POSIX signature],
+      [gl_cv_func_gettimeofday_posix_signature],
+      [AC_COMPILE_IFELSE(
+         [AC_LANG_PROGRAM(
+            [[#include <sys/time.h>
+              struct timeval c;
+              int gettimeofday (struct timeval *restrict, void *restrict);
+            ]],
+            [[/* glibc uses struct timezone * rather than the POSIX void *
+                 if _GNU_SOURCE is defined.  However, since the only portable
+                 use of gettimeofday uses NULL as the second parameter, and
+                 since the glibc definition is actually more typesafe, it is
+                 not worth wrapping this to get a compliant signature.  */
+              int (*f) (struct timeval *restrict, void *restrict)
+                = gettimeofday;
+              int x = f (&c, 0);
+              return !(x | c.tv_sec | c.tv_usec);
+            ]])],
+          [gl_cv_func_gettimeofday_posix_signature=yes],
+          [AC_COMPILE_IFELSE(
+            [AC_LANG_PROGRAM(
+              [[#include <sys/time.h>
+int gettimeofday (struct timeval *restrict, struct timezone *restrict);
+              ]])],
+            [gl_cv_func_gettimeofday_posix_signature=almost],
+            [gl_cv_func_gettimeofday_posix_signature=no])])])
+    if test $gl_cv_func_gettimeofday_posix_signature = almost; then
+      gl_gettimeofday_timezone='struct timezone'
+    elif test $gl_cv_func_gettimeofday_posix_signature != yes; then
+      REPLACE_GETTIMEOFDAY=1
+    fi
+    dnl If we override 'struct timeval', we also have to override gettimeofday.
+    if test $REPLACE_STRUCT_TIMEVAL = 1; then
+      REPLACE_GETTIMEOFDAY=1
+    fi
+    m4_ifdef([gl_FUNC_TZSET_CLOBBER], [
+      gl_FUNC_TZSET_CLOBBER
+      case "$gl_cv_func_tzset_clobber" in
+        *yes)
+          REPLACE_GETTIMEOFDAY=1
+          gl_GETTIMEOFDAY_REPLACE_LOCALTIME
+          AC_DEFINE([tzset], [rpl_tzset],
+            [Define to rpl_tzset if the wrapper function should be used.])
+          AC_DEFINE([TZSET_CLOBBERS_LOCALTIME], [1],
+            [Define if tzset clobbers localtime's static buffer.])
+          ;;
+      esac
+    ])
+  fi
+  AC_DEFINE_UNQUOTED([GETTIMEOFDAY_TIMEZONE], [$gl_gettimeofday_timezone],
+    [Define this to 'void' or 'struct timezone' to match the system's
+     declaration of the second argument to gettimeofday.])
+])
+
+
+dnl See if gettimeofday clobbers the static buffer that localtime uses
+dnl for its return value.  The gettimeofday function from Mac OS X 10.0.4
+dnl (i.e., Darwin 1.3.7) has this problem.
+dnl
+dnl If it does, then arrange to use gettimeofday and localtime only via
+dnl the wrapper functions that work around the problem.
+
+AC_DEFUN([gl_FUNC_GETTIMEOFDAY_CLOBBER],
+[
+ AC_REQUIRE([gl_HEADER_SYS_TIME_H])
+ AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+
+ AC_CACHE_CHECK([whether gettimeofday clobbers localtime buffer],
+  [gl_cv_func_gettimeofday_clobber],
+  [AC_RUN_IFELSE(
+     [AC_LANG_PROGRAM(
+        [[#include <string.h>
+          #include <sys/time.h>
+          #include <time.h>
+          #include <stdlib.h>
+        ]],
+        [[
+          time_t t = 0;
+          struct tm *lt;
+          struct tm saved_lt;
+          struct timeval tv;
+          lt = localtime (&t);
+          saved_lt = *lt;
+          gettimeofday (&tv, NULL);
+          return memcmp (lt, &saved_lt, sizeof (struct tm)) != 0;
+        ]])],
+     [gl_cv_func_gettimeofday_clobber=no],
+     [gl_cv_func_gettimeofday_clobber=yes],
+     [# When cross-compiling:
+      case "$host_os" in
+                # Guess all is fine on glibc systems.
+        *-gnu*) gl_cv_func_gettimeofday_clobber="guessing no" ;;
+                # If we don't know, assume the worst.
+        *)      gl_cv_func_gettimeofday_clobber="guessing yes" ;;
+      esac
+     ])])
+
+ case "$gl_cv_func_gettimeofday_clobber" in
+   *yes)
+     REPLACE_GETTIMEOFDAY=1
+     gl_GETTIMEOFDAY_REPLACE_LOCALTIME
+     AC_DEFINE([GETTIMEOFDAY_CLOBBERS_LOCALTIME], [1],
+       [Define if gettimeofday clobbers the localtime buffer.])
+     ;;
+ esac
+])
+
+AC_DEFUN([gl_GETTIMEOFDAY_REPLACE_LOCALTIME], [
+  REPLACE_GMTIME=1
+  REPLACE_LOCALTIME=1
+])
+
+# Prerequisites of lib/gettimeofday.c.
+AC_DEFUN([gl_PREREQ_GETTIMEOFDAY], [
+  AC_CHECK_HEADERS([sys/timeb.h])
+  AC_CHECK_FUNCS([_ftime])
+])
diff --git a/gl/m4/sys_socket_h.m4 b/gl/m4/sys_socket_h.m4
new file mode 100644
index 00000000..114d8281
--- /dev/null
+++ b/gl/m4/sys_socket_h.m4
@@ -0,0 +1,176 @@
+# sys_socket_h.m4 serial 23
+dnl Copyright (C) 2005-2014 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl From Simon Josefsson.
+
+AC_DEFUN([gl_HEADER_SYS_SOCKET],
+[
+  AC_REQUIRE([gl_SYS_SOCKET_H_DEFAULTS])
+  AC_REQUIRE([AC_CANONICAL_HOST])
+
+  dnl On OSF/1, the functions recv(), send(), recvfrom(), sendto() have
+  dnl old-style declarations (with return type 'int' instead of 'ssize_t')
+  dnl unless _POSIX_PII_SOCKET is defined.
+  case "$host_os" in
+    osf*)
+      AC_DEFINE([_POSIX_PII_SOCKET], [1],
+        [Define to 1 in order to get the POSIX compatible declarations
+         of socket functions.])
+      ;;
+  esac
+
+  AC_CACHE_CHECK([whether <sys/socket.h> is self-contained],
+    [gl_cv_header_sys_socket_h_selfcontained],
+    [
+      AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[#include <sys/socket.h>]], [[]])],
+        [gl_cv_header_sys_socket_h_selfcontained=yes],
+        [gl_cv_header_sys_socket_h_selfcontained=no])
+    ])
+  if test $gl_cv_header_sys_socket_h_selfcontained = yes; then
+    dnl If the shutdown function exists, <sys/socket.h> should define
+    dnl SHUT_RD, SHUT_WR, SHUT_RDWR.
+    AC_CHECK_FUNCS([shutdown])
+    if test $ac_cv_func_shutdown = yes; then
+      AC_CACHE_CHECK([whether <sys/socket.h> defines the SHUT_* macros],
+        [gl_cv_header_sys_socket_h_shut],
+        [
+          AC_COMPILE_IFELSE(
+            [AC_LANG_PROGRAM([[#include <sys/socket.h>]],
+               [[int a[] = { SHUT_RD, SHUT_WR, SHUT_RDWR };]])],
+            [gl_cv_header_sys_socket_h_shut=yes],
+            [gl_cv_header_sys_socket_h_shut=no])
+        ])
+      if test $gl_cv_header_sys_socket_h_shut = no; then
+        SYS_SOCKET_H='sys/socket.h'
+      fi
+    fi
+  fi
+  # We need to check for ws2tcpip.h now.
+  gl_PREREQ_SYS_H_SOCKET
+  AC_CHECK_TYPES([struct sockaddr_storage, sa_family_t],,,[
+  /* sys/types.h is not needed according to POSIX, but the
+     sys/socket.h in i386-unknown-freebsd4.10 and
+     powerpc-apple-darwin5.5 required it. */
+#include <sys/types.h>
+#ifdef HAVE_SYS_SOCKET_H
+#include <sys/socket.h>
+#endif
+#ifdef HAVE_WS2TCPIP_H
+#include <ws2tcpip.h>
+#endif
+])
+  if test $ac_cv_type_struct_sockaddr_storage = no; then
+    HAVE_STRUCT_SOCKADDR_STORAGE=0
+  fi
+  if test $ac_cv_type_sa_family_t = no; then
+    HAVE_SA_FAMILY_T=0
+  fi
+  if test $ac_cv_type_struct_sockaddr_storage != no; then
+    AC_CHECK_MEMBERS([struct sockaddr_storage.ss_family],
+      [],
+      [HAVE_STRUCT_SOCKADDR_STORAGE_SS_FAMILY=0],
+      [#include <sys/types.h>
+       #ifdef HAVE_SYS_SOCKET_H
+       #include <sys/socket.h>
+       #endif
+       #ifdef HAVE_WS2TCPIP_H
+       #include <ws2tcpip.h>
+       #endif
+      ])
+  fi
+  if test $HAVE_STRUCT_SOCKADDR_STORAGE = 0 || test $HAVE_SA_FAMILY_T = 0 \
+     || test $HAVE_STRUCT_SOCKADDR_STORAGE_SS_FAMILY = 0; then
+    SYS_SOCKET_H='sys/socket.h'
+  fi
+  gl_PREREQ_SYS_H_WINSOCK2
+
+  dnl Check for declarations of anything we want to poison if the
+  dnl corresponding gnulib module is not in use.
+  gl_WARN_ON_USE_PREPARE([[
+/* Some systems require prerequisite headers.  */
+#include <sys/types.h>
+#include <sys/socket.h>
+    ]], [socket connect accept bind getpeername getsockname getsockopt
+    listen recv send recvfrom sendto setsockopt shutdown accept4])
+])
+
+AC_DEFUN([gl_PREREQ_SYS_H_SOCKET],
+[
+  dnl Check prerequisites of the <sys/socket.h> replacement.
+  AC_REQUIRE([gl_CHECK_SOCKET_HEADERS])
+  gl_CHECK_NEXT_HEADERS([sys/socket.h])
+  if test $ac_cv_header_sys_socket_h = yes; then
+    HAVE_SYS_SOCKET_H=1
+    HAVE_WS2TCPIP_H=0
+  else
+    HAVE_SYS_SOCKET_H=0
+    if test $ac_cv_header_ws2tcpip_h = yes; then
+      HAVE_WS2TCPIP_H=1
+    else
+      HAVE_WS2TCPIP_H=0
+    fi
+  fi
+  AC_SUBST([HAVE_SYS_SOCKET_H])
+  AC_SUBST([HAVE_WS2TCPIP_H])
+])
+
+# Common prerequisites of the <sys/socket.h> replacement and of the
+# <sys/select.h> replacement.
+# Sets and substitutes HAVE_WINSOCK2_H.
+AC_DEFUN([gl_PREREQ_SYS_H_WINSOCK2],
+[
+  m4_ifdef([gl_UNISTD_H_DEFAULTS], [AC_REQUIRE([gl_UNISTD_H_DEFAULTS])])
+  m4_ifdef([gl_SYS_IOCTL_H_DEFAULTS], [AC_REQUIRE([gl_SYS_IOCTL_H_DEFAULTS])])
+  AC_CHECK_HEADERS_ONCE([sys/socket.h])
+  if test $ac_cv_header_sys_socket_h != yes; then
+    dnl We cannot use AC_CHECK_HEADERS_ONCE here, because that would make
+    dnl the check for those headers unconditional; yet cygwin reports
+    dnl that the headers are present but cannot be compiled (since on
+    dnl cygwin, all socket information should come from sys/socket.h).
+    AC_CHECK_HEADERS([winsock2.h])
+  fi
+  if test "$ac_cv_header_winsock2_h" = yes; then
+    HAVE_WINSOCK2_H=1
+    UNISTD_H_HAVE_WINSOCK2_H=1
+    SYS_IOCTL_H_HAVE_WINSOCK2_H=1
+  else
+    HAVE_WINSOCK2_H=0
+  fi
+  AC_SUBST([HAVE_WINSOCK2_H])
+])
+
+AC_DEFUN([gl_SYS_SOCKET_MODULE_INDICATOR],
+[
+  dnl Use AC_REQUIRE here, so that the default settings are expanded once only.
+  AC_REQUIRE([gl_SYS_SOCKET_H_DEFAULTS])
+  gl_MODULE_INDICATOR_SET_VARIABLE([$1])
+  dnl Define it also as a C macro, for the benefit of the unit tests.
+  gl_MODULE_INDICATOR_FOR_TESTS([$1])
+])
+
+AC_DEFUN([gl_SYS_SOCKET_H_DEFAULTS],
+[
+  GNULIB_SOCKET=0;      AC_SUBST([GNULIB_SOCKET])
+  GNULIB_CONNECT=0;     AC_SUBST([GNULIB_CONNECT])
+  GNULIB_ACCEPT=0;      AC_SUBST([GNULIB_ACCEPT])
+  GNULIB_BIND=0;        AC_SUBST([GNULIB_BIND])
+  GNULIB_GETPEERNAME=0; AC_SUBST([GNULIB_GETPEERNAME])
+  GNULIB_GETSOCKNAME=0; AC_SUBST([GNULIB_GETSOCKNAME])
+  GNULIB_GETSOCKOPT=0;  AC_SUBST([GNULIB_GETSOCKOPT])
+  GNULIB_LISTEN=0;      AC_SUBST([GNULIB_LISTEN])
+  GNULIB_RECV=0;        AC_SUBST([GNULIB_RECV])
+  GNULIB_SEND=0;        AC_SUBST([GNULIB_SEND])
+  GNULIB_RECVFROM=0;    AC_SUBST([GNULIB_RECVFROM])
+  GNULIB_SENDTO=0;      AC_SUBST([GNULIB_SENDTO])
+  GNULIB_SETSOCKOPT=0;  AC_SUBST([GNULIB_SETSOCKOPT])
+  GNULIB_SHUTDOWN=0;    AC_SUBST([GNULIB_SHUTDOWN])
+  GNULIB_ACCEPT4=0;     AC_SUBST([GNULIB_ACCEPT4])
+  HAVE_STRUCT_SOCKADDR_STORAGE=1; AC_SUBST([HAVE_STRUCT_SOCKADDR_STORAGE])
+  HAVE_STRUCT_SOCKADDR_STORAGE_SS_FAMILY=1;
+                        AC_SUBST([HAVE_STRUCT_SOCKADDR_STORAGE_SS_FAMILY])
+  HAVE_SA_FAMILY_T=1;   AC_SUBST([HAVE_SA_FAMILY_T])
+  HAVE_ACCEPT4=1;       AC_SUBST([HAVE_ACCEPT4])
+])
diff --git a/gl/m4/sys_time_h.m4 b/gl/m4/sys_time_h.m4
new file mode 100644
index 00000000..5c79300f
--- /dev/null
+++ b/gl/m4/sys_time_h.m4
@@ -0,0 +1,110 @@
+# Configure a replacement for <sys/time.h>.
+# serial 8
+
+# Copyright (C) 2007, 2009-2014 Free Software Foundation, Inc.
+# This file is free software; the Free Software Foundation
+# gives unlimited permission to copy and/or distribute it,
+# with or without modifications, as long as this notice is preserved.
+
+# Written by Paul Eggert and Martin Lambers.
+
+AC_DEFUN([gl_HEADER_SYS_TIME_H],
+[
+  dnl Use AC_REQUIRE here, so that the REPLACE_GETTIMEOFDAY=0 statement
+  dnl below is expanded once only, before all REPLACE_GETTIMEOFDAY=1
+  dnl statements that occur in other macros.
+  AC_REQUIRE([gl_HEADER_SYS_TIME_H_BODY])
+])
+
+AC_DEFUN([gl_HEADER_SYS_TIME_H_BODY],
+[
+  AC_REQUIRE([AC_C_RESTRICT])
+  AC_REQUIRE([gl_HEADER_SYS_TIME_H_DEFAULTS])
+  AC_CHECK_HEADERS_ONCE([sys/time.h])
+  gl_CHECK_NEXT_HEADERS([sys/time.h])
+
+  if test $ac_cv_header_sys_time_h != yes; then
+    HAVE_SYS_TIME_H=0
+  fi
+
+  dnl On native Windows with MSVC, 'struct timeval' is defined in <winsock2.h>
+  dnl only. So include that header in the list.
+  gl_PREREQ_SYS_H_WINSOCK2
+  AC_CACHE_CHECK([for struct timeval], [gl_cv_sys_struct_timeval],
+    [AC_COMPILE_IFELSE(
+       [AC_LANG_PROGRAM(
+          [[#if HAVE_SYS_TIME_H
+             #include <sys/time.h>
+            #endif
+            #include <time.h>
+            #if HAVE_WINSOCK2_H
+            # include <winsock2.h>
+            #endif
+          ]],
+          [[static struct timeval x; x.tv_sec = x.tv_usec;]])],
+       [gl_cv_sys_struct_timeval=yes],
+       [gl_cv_sys_struct_timeval=no])
+    ])
+  if test $gl_cv_sys_struct_timeval != yes; then
+    HAVE_STRUCT_TIMEVAL=0
+  else
+    dnl On native Windows with a 64-bit 'time_t', 'struct timeval' is defined
+    dnl (in <sys/time.h> and <winsock2.h> for mingw64, in <winsock2.h> only
+    dnl for MSVC) with a tv_sec field of type 'long' (32-bit!), which is
+    dnl smaller than the 'time_t' type mandated by POSIX.
+    dnl On OpenBSD 5.1 amd64, tv_sec is 64 bits and time_t 32 bits, but
+    dnl that is good enough.
+    AC_CACHE_CHECK([for wide-enough struct timeval.tv_sec member],
+      [gl_cv_sys_struct_timeval_tv_sec],
+      [AC_COMPILE_IFELSE(
+         [AC_LANG_PROGRAM(
+            [[#if HAVE_SYS_TIME_H
+               #include <sys/time.h>
+              #endif
+              #include <time.h>
+              #if HAVE_WINSOCK2_H
+              # include <winsock2.h>
+              #endif
+            ]],
+            [[static struct timeval x;
+              typedef int verify_tv_sec_type[
+                sizeof (time_t) <= sizeof x.tv_sec ? 1 : -1
+              ];
+            ]])],
+         [gl_cv_sys_struct_timeval_tv_sec=yes],
+         [gl_cv_sys_struct_timeval_tv_sec=no])
+      ])
+    if test $gl_cv_sys_struct_timeval_tv_sec != yes; then
+      REPLACE_STRUCT_TIMEVAL=1
+    fi
+  fi
+
+  dnl Check for declarations of anything we want to poison if the
+  dnl corresponding gnulib module is not in use.
+  gl_WARN_ON_USE_PREPARE([[
+#if HAVE_SYS_TIME_H
+# include <sys/time.h>
+#endif
+#include <time.h>
+    ]], [gettimeofday])
+])
+
+AC_DEFUN([gl_SYS_TIME_MODULE_INDICATOR],
+[
+  dnl Use AC_REQUIRE here, so that the default settings are expanded once only.
+  AC_REQUIRE([gl_HEADER_SYS_TIME_H_DEFAULTS])
+  gl_MODULE_INDICATOR_SET_VARIABLE([$1])
+  dnl Define it also as a C macro, for the benefit of the unit tests.
+  gl_MODULE_INDICATOR_FOR_TESTS([$1])
+])
+
+AC_DEFUN([gl_HEADER_SYS_TIME_H_DEFAULTS],
+[
+  GNULIB_GETTIMEOFDAY=0;     AC_SUBST([GNULIB_GETTIMEOFDAY])
+  dnl Assume POSIX behavior unless another module says otherwise.
+  HAVE_GETTIMEOFDAY=1;       AC_SUBST([HAVE_GETTIMEOFDAY])
+  HAVE_STRUCT_TIMEVAL=1;     AC_SUBST([HAVE_STRUCT_TIMEVAL])
+  HAVE_SYS_TIME_H=1;         AC_SUBST([HAVE_SYS_TIME_H])
+  REPLACE_GETTIMEOFDAY=0;    AC_SUBST([REPLACE_GETTIMEOFDAY])
+  REPLACE_STRUCT_TIMEVAL=0;  AC_SUBST([REPLACE_STRUCT_TIMEVAL])
+])
diff --git a/gl/sys_time.in.h b/gl/sys_time.in.h
new file mode 100644
index 00000000..af11da85
--- /dev/null
+++ b/gl/sys_time.in.h
@@ -0,0 +1,213 @@
+/* Provide a more complete sys/time.h.
+
+   Copyright (C) 2007-2014 Free Software Foundation, Inc.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU Lesser General Public License as published by
+   the Free Software Foundation; either version 2.1, or (at your option)
+   any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public License
+   along with this program; if not, see <http://www.gnu.org/licenses/>.  */
+
+/* Written by Paul Eggert.  */
+
+#ifndef _@GUARD_PREFIX@_SYS_TIME_H
+
+#if __GNUC__ >= 3
+@PRAGMA_SYSTEM_HEADER@
+#endif
+@PRAGMA_COLUMNS@
+
+/* On Cygwin and on many BSDish systems, <sys/time.h> includes itself
+   recursively via <sys/select.h>.
+   Simply delegate to the system's header in this case; it is a no-op.
+   Without this extra ifdef, the C++ gettimeofday declaration below
+   would be a forward declaration in gnulib's nested <sys/time.h>.  */
+#if defined _CYGWIN_SYS_TIME_H || defined _SYS_TIME_H || defined _SYS_TIME_H_
+# @INCLUDE_NEXT@ @NEXT_SYS_TIME_H@
+#else
+
+/* The include_next requires a split double-inclusion guard.  */
+#if @HAVE_SYS_TIME_H@
+# @INCLUDE_NEXT@ @NEXT_SYS_TIME_H@
+#endif
+
+#ifndef _@GUARD_PREFIX@_SYS_TIME_H
+#define _@GUARD_PREFIX@_SYS_TIME_H
+
+#if ! @HAVE_SYS_TIME_H@
+# include <time.h>
+#endif
+
+/* On native Windows with MSVC, get the 'struct timeval' type.
+   Also, on native Windows with a 64-bit time_t, where we are overriding the
+   'struct timeval' type, get all declarations of system functions whose
+   signature contains 'struct timeval'.  */
+#if (defined _MSC_VER || @REPLACE_STRUCT_TIMEVAL@) && @HAVE_WINSOCK2_H@ && !defined _GL_INCLUDING_WINSOCK2_H
+# define _GL_INCLUDING_WINSOCK2_H
+# include <winsock2.h>
+# undef _GL_INCLUDING_WINSOCK2_H
+#endif
+
+/* The definitions of _GL_FUNCDECL_RPL etc. are copied here.  */
+
+/* The definition of _GL_ARG_NONNULL is copied here.  */
+
+/* The definition of _GL_WARN_ON_USE is copied here.  */
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#if !@HAVE_STRUCT_TIMEVAL@ || @REPLACE_STRUCT_TIMEVAL@
+
+# if @REPLACE_STRUCT_TIMEVAL@
+#  define timeval rpl_timeval
+# endif
+
+# if !GNULIB_defined_struct_timeval
+struct timeval
+{
+  time_t tv_sec;
+  long int tv_usec;
+};
+#  define GNULIB_defined_struct_timeval 1
+# endif
+
+#endif
+
+#ifdef __cplusplus
+}
+#endif
+
+#if @GNULIB_GETTIMEOFDAY@
+# if @REPLACE_GETTIMEOFDAY@
+#  if !(defined __cplusplus && defined GNULIB_NAMESPACE)
+#   undef gettimeofday
+#   define gettimeofday rpl_gettimeofday
+#  endif
+_GL_FUNCDECL_RPL (gettimeofday, int,
+                  (struct timeval *restrict, void *restrict)
+                  _GL_ARG_NONNULL ((1)));
+_GL_CXXALIAS_RPL (gettimeofday, int,
+                  (struct timeval *restrict, void *restrict));
+# else
+#  if !@HAVE_GETTIMEOFDAY@
+_GL_FUNCDECL_SYS (gettimeofday, int,
+                  (struct timeval *restrict, void *restrict)
+                  _GL_ARG_NONNULL ((1)));
+#  endif
+/* Need to cast, because on glibc systems, by default, the second argument is
+                                                  struct timezone *.  */
+_GL_CXXALIAS_SYS_CAST (gettimeofday, int,
+                       (struct timeval *restrict, void *restrict));
+# endif
+_GL_CXXALIASWARN (gettimeofday);
+#elif defined GNULIB_POSIXCHECK
+# undef gettimeofday
+# if HAVE_RAW_DECL_GETTIMEOFDAY
+_GL_WARN_ON_USE (gettimeofday, "gettimeofday is unportable - "
+                 "use gnulib module gettimeofday for portability");
+# endif
+#endif
+
+/* Hide some function declarations from <winsock2.h>.  */
+
+#if defined _MSC_VER && @HAVE_WINSOCK2_H@
+# if !defined _@GUARD_PREFIX@_UNISTD_H
+#  if !(defined __cplusplus && defined GNULIB_NAMESPACE)
+#   undef close
+#   define close close_used_without_including_unistd_h
+#  else
+     _GL_WARN_ON_USE (close,
+                      "close() used without including <unistd.h>");
+#  endif
+#  if !(defined __cplusplus && defined GNULIB_NAMESPACE)
+#   undef gethostname
+#   define gethostname gethostname_used_without_including_unistd_h
+#  else
+     _GL_WARN_ON_USE (gethostname,
+                      "gethostname() used without including <unistd.h>");
+#  endif
+# endif
+# if !defined _@GUARD_PREFIX@_SYS_SOCKET_H
+#  if !(defined __cplusplus && defined GNULIB_NAMESPACE)
+#   undef socket
+#   define socket              socket_used_without_including_sys_socket_h
+#   undef connect
+#   define connect             connect_used_without_including_sys_socket_h
+#   undef accept
+#   define accept              accept_used_without_including_sys_socket_h
+#   undef bind
+#   define bind                bind_used_without_including_sys_socket_h
+#   undef getpeername
+#   define getpeername         getpeername_used_without_including_sys_socket_h
+#   undef getsockname
+#   define getsockname         getsockname_used_without_including_sys_socket_h
+#   undef getsockopt
+#   define getsockopt          getsockopt_used_without_including_sys_socket_h
+#   undef listen
+#   define listen              listen_used_without_including_sys_socket_h
+#   undef recv
+#   define recv                recv_used_without_including_sys_socket_h
+#   undef send
+#   define send                send_used_without_including_sys_socket_h
+#   undef recvfrom
+#   define recvfrom            recvfrom_used_without_including_sys_socket_h
+#   undef sendto
+#   define sendto              sendto_used_without_including_sys_socket_h
+#   undef setsockopt
+#   define setsockopt          setsockopt_used_without_including_sys_socket_h
+#   undef shutdown
+#   define shutdown            shutdown_used_without_including_sys_socket_h
+#  else
+     _GL_WARN_ON_USE (socket,
+                      "socket() used without including <sys/socket.h>");
+     _GL_WARN_ON_USE (connect,
+                      "connect() used without including <sys/socket.h>");
+     _GL_WARN_ON_USE (accept,
+                      "accept() used without including <sys/socket.h>");
+     _GL_WARN_ON_USE (bind,
+                      "bind() used without including <sys/socket.h>");
+     _GL_WARN_ON_USE (getpeername,
+                      "getpeername() used without including <sys/socket.h>");
+     _GL_WARN_ON_USE (getsockname,
+                      "getsockname() used without including <sys/socket.h>");
+     _GL_WARN_ON_USE (getsockopt,
+                      "getsockopt() used without including <sys/socket.h>");
+     _GL_WARN_ON_USE (listen,
+                      "listen() used without including <sys/socket.h>");
+     _GL_WARN_ON_USE (recv,
+                      "recv() used without including <sys/socket.h>");
+     _GL_WARN_ON_USE (send,
+                      "send() used without including <sys/socket.h>");
+     _GL_WARN_ON_USE (recvfrom,
+                      "recvfrom() used without including <sys/socket.h>");
+     _GL_WARN_ON_USE (sendto,
+                      "sendto() used without including <sys/socket.h>");
+     _GL_WARN_ON_USE (setsockopt,
+                      "setsockopt() used without including <sys/socket.h>");
+     _GL_WARN_ON_USE (shutdown,
+                      "shutdown() used without including <sys/socket.h>");
+#  endif
+# endif
+# if !defined _@GUARD_PREFIX@_SYS_SELECT_H
+#  if !(defined __cplusplus && defined GNULIB_NAMESPACE)
+#   undef select
+#   define select select_used_without_including_sys_select_h
+#  else
+     _GL_WARN_ON_USE (select,
+                      "select() used without including <sys/select.h>");
+#  endif
+# endif
+#endif
+
+#endif /* _@GUARD_PREFIX@_SYS_TIME_H */
+#endif /* _CYGWIN_SYS_TIME_H */
+#endif /* _@GUARD_PREFIX@_SYS_TIME_H */