https://github.com/rizsotto/Bear/pull/521

From 472cbed312444cdcef9102e924c79070ea1d3ab2 Mon Sep 17 00:00:00 2001
From: Florian Weimer <fweimer@redhat.com>
Date: Sat, 15 Apr 2023 19:37:41 +0200
Subject: [PATCH] Avoid implicit function declarations in tests, for C99
 compatibility

Include <stdio.h> for printf and define _GNU_SOURCE for execvpe.

Future compilers will not support implicit function declartions by
default, causing these tests to fail to build.
--- a/test/cases/intercept/preload/errno_reset.c
+++ b/test/cases/intercept/preload/errno_reset.c
@@ -5,6 +5,7 @@
 #include <stdlib.h>
 #include <errno.h>
 #include <string.h>
+#include <stdio.h>
 
 int main()
 {
--- a/test/cases/intercept/preload/posix/execvpe/success.c
+++ b/test/cases/intercept/preload/posix/execvpe/success.c
@@ -8,6 +8,7 @@
 #include "config.h"
 
 #if defined HAVE_UNISTD_H
+#define _GNU_SOURCE
 #include <unistd.h>
 #endif