Author: Andreas Beckmann <anbe@debian.org>
Description: fix building with -Werror=implicit-function-declaration

--- a/libast.m4
+++ b/libast.m4
@@ -441,6 +441,7 @@ AC_DEFUN([dps_snprintf_oflow], [
         AC_TRY_RUN(
             changequote(<<, >>)dnl
 <<#include <stdio.h>
+#include <stdlib.h>
 
 #ifndef HAVE_SNPRINTF
 #include "src/snprintf.c"