Added missing files

build-aux/snippet/arg-nonnull.h

@@ -0,0 +1,26 @@
+/* A C macro for declaring that specific arguments must not be NULL.
+   Copyright (C) 2009-2013 Free Software Foundation, Inc.
+
+   This program is free software: you can redistribute it and/or modify it
+   under the terms of the GNU General Public License as published
+   by the Free Software Foundation; either version 3 of the License, 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
+   General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+/* _GL_ARG_NONNULL((n,...,m)) tells the compiler and static analyzer tools
+   that the values passed as arguments n, ..., m must be non-NULL pointers.
+   n = 1 stands for the first argument, n = 2 for the second argument etc.  */
+#ifndef _GL_ARG_NONNULL
+# if (__GNUC__ == 3 && __GNUC_MINOR__ >= 3) || __GNUC__ > 3
+#  define _GL_ARG_NONNULL(params) __attribute__ ((__nonnull__ params))
+# else
+#  define _GL_ARG_NONNULL(params)
+# endif
+#endif