Use a compatible with BSD's setproctitle.

src/setproctitle.c

@@ -17,15 +17,24 @@
  */
 
 #include <config.h>
+#include <stdarg.h>
+#include <stdio.h>
 #include <sys/prctl.h>
 
 /* This sets the proccess title as shown in top, but not in ps (*@#%@).
  * To change the ps name in Linux, one needs to do master black magic
  * trickery (set util-linux setproctitle).
  */
-void setproctitle (const char *prog)
+void setproctitle (const char *fmt, ...)
 {
 #ifdef PR_SET_NAME
-	prctl (PR_SET_NAME, prog);
+	char name[16];
+	va_list args;
+
+	va_start(args, fmt);
+	vsnprintf(name, sizeof(name)-1, fmt, args);
+	va_end(args);
+
+	prctl (PR_SET_NAME, name);
 #endif
 }

src/setproctitle.h

@@ -1,6 +1,7 @@
 #ifndef SETPROCTITLE_H
 # define SETPROCTITLE_H
 
-extern void setproctitle (const char *prog);
+void __attribute__ ((format(printf, 1, 2)))
+setproctitle(const char *fmt, ...);
 
 #endif