diff --git a/src/haproxy.c b/src/haproxy.c
index b94252d..20480a1 100644
--- a/src/haproxy.c
+++ b/src/haproxy.c
@@ -25,6 +25,7 @@
  *
  */
 
+#define _GNU_SOURCE
 #include <stdio.h>
 #include <stdlib.h>
 #include <unistd.h>
@@ -47,9 +48,7 @@
 #include <syslog.h>
 #include <grp.h>
 #ifdef USE_CPU_AFFINITY
-#define __USE_GNU
 #include <sched.h>
-#undef __USE_GNU
 #endif
 
 #ifdef DEBUG_FULL