https://github.com/oetiker/rrdtool-1.x/commit/f3334fcbde0a77aa48938ba38602bff91c09cf85

From f3334fcbde0a77aa48938ba38602bff91c09cf85 Mon Sep 17 00:00:00 2001
From: Ryan Schmidt <git@ryandesign.com>
Date: Sun, 20 Mar 2022 16:29:10 -0500
Subject: [PATCH] acinclude.m4: Include <stdlib.h> when using exit

Fixes:

conftest.c:124:33: error: implicitly declaring library function 'exit'
with type 'void (int) __attribute__((noreturn))'
--- a/m4/acinclude.m4
+++ b/m4/acinclude.m4
@@ -582,7 +582,8 @@ AC_DEFUN([GC_TIMEZONE], [
         AC_REQUIRE([AC_STRUCT_TM])
         AC_CACHE_CHECK([tm_gmtoff in struct tm], gq_cv_have_tm_gmtoff,
                 gq_cv_have_tm_gmtoff=no
-                AC_TRY_COMPILE([#include <time.h>
+                AC_TRY_COMPILE([#include <stdlib.h>
+                                #include <time.h>
                                 #include <$ac_cv_struct_tm>
                                 ],
                                [struct tm t;
@@ -595,7 +596,8 @@ AC_DEFUN([GC_TIMEZONE], [
 
         AC_CACHE_CHECK([__tm_gmtoff in struct tm], gq_cv_have___tm_gmtoff,
                 gq_cv_have___tm_gmtoff=no
-                AC_TRY_COMPILE([#include <time.h>
+                AC_TRY_COMPILE([#include <stdlib.h>
+                                #include <time.h>
                                 #include <$ac_cv_struct_tm>
                                 ],
                                [struct tm t;