diff '--color=auto' -ruN gnokii-0.6.31.orig/configure.in gnokii-0.6.31/configure.in
--- gnokii-0.6.31.orig/configure.in	2024-11-16 14:59:39.416370347 +0100
+++ gnokii-0.6.31/configure.in	2024-11-16 15:03:09.368586626 +0100
@@ -940,6 +940,7 @@
 AC_CACHE_CHECK(for ISO C99 compliant snprintf,ac_cv_func_snprintf_c99,
 	[AC_TRY_RUN([
 #include <stdio.h>
+#include <stdlib.h>
 
 int main()
 {
@@ -955,6 +956,7 @@
 	[AC_TRY_RUN([
 #include <stdio.h>
 #include <stdarg.h>
+#include <stdlib.h>
 
 int doit(char *buf, int len, const char *s, ...)
 {