Fix: menus.c:2374: warning: implicit declaration of function `putenv`

Ensure _GNU_SOURCE is defined on Linux builds before including <stdlib.h>
so the prototype is exposed in the header properly.

https://bugs.freedesktop.org/show_bug.cgi?id=32696

Signed-off-by: Alan Coopersmith <alan.coopersmith@oracle.com>
Reviewed-by: Julien Cristau <jcristau@debian.org>

1 files changed, 4 insertions, 0 deletions

diff --git a/src/twm.h b/src/twm.h
index 420d6c8..6e2bb27 100644
--- a/src/twm.h
+++ b/src/twm.h
@@ -62,6 +62,10 @@ from The Open Group.
 #ifndef _TWM_
 #define _TWM_
 
+#ifdef HAVE_CONFIG_H
+# include "config.h"
+#endif
+
 #include <X11/Xlib.h>
 #include <X11/Xutil.h>
 #include <X11/cursorfont.h>