2 files changed, 4 insertions, 0 deletions

diff --git a/ChangeLog b/ChangeLog
index 6c13bb9b8..ce612d315 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -3,6 +3,8 @@
    Hands' greatly revised version.
  - (djm) Release 6.2p1
  - (dtucker) [configure.ac] Add stdlib.h to zlib check for exit() prototype.
+ - (dtucker) [includes.h] Check if _GNU_SOURCE is already defined before
+   defining it again.  Prevents warnings if someone, eg, sets it in CFLAGS.
 
 20120318
  - (djm) [configure.ac log.c scp.c sshconnect2.c openbsd-compat/vis.c]
diff --git a/includes.h b/includes.h
index 3e206c899..07bcd89f2 100644
--- a/includes.h
+++ b/includes.h
@@ -18,7 +18,9 @@
 
 #include "config.h"
 
+#ifndef _GNU_SOURCE
 #define _GNU_SOURCE /* activate extra prototypes for glibc */
+#endif
 
 #include <sys/types.h>
 #include <sys/socket.h> /* For CMSG_* */