1 files changed, 2 insertions, 0 deletions
diff --git a/afl-fuzz.c b/afl-fuzz.c
index 8f4e1344..f974268f 100644
--- a/afl-fuzz.c
+++ b/afl-fuzz.c
@@ -23,7 +23,9 @@
 #define AFL_MAIN
 #define MESSAGES_TO_STDOUT
 
+#ifndef _GNU_SOURCE
 #define _GNU_SOURCE
+#endif
 #define _FILE_OFFSET_BITS 64
 
 #include "config.h"