diff --git a/admin/vgsuppression.c b/admin/vgsuppression.c
index 0e1f41fca..cad026e52 100644
--- a/admin/vgsuppression.c
+++ b/admin/vgsuppression.c
@@ -18,7 +18,6 @@
   along with this program; if not, write to the Free Software
   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */
-#define _GNU_SOURCE
 
 /*
   just place any problematic calls where valgrind whines about in main (with comments please)
diff --git a/src/lib/rwlock.c b/src/lib/rwlock.c
index 0862aa808..092c7b54b 100644
--- a/src/lib/rwlock.c
+++ b/src/lib/rwlock.c
@@ -18,8 +18,6 @@
   along with this program; if not, write to the Free Software
   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */
-#define _GNU_SOURCE
-
 #include <errno.h>
 #include "lib/rwlock.h"
 
diff --git a/src/lib/safeclib.c b/src/lib/safeclib.c
index 71e347ab7..a0b562643 100644
--- a/src/lib/safeclib.c
+++ b/src/lib/safeclib.c
@@ -18,8 +18,6 @@
   along with this program; if not, write to the Free Software
   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */
-#define _GNU_SOURCE
-
 #include "error.h"
 
 #include <string.h>