diff --git a/src/hb.hh b/src/hb.hh
index 802a5a0fe..77ef3f86b 100644
--- a/src/hb.hh
+++ b/src/hb.hh
@@ -29,8 +29,6 @@
 #ifndef HB_HH
 #define HB_HH
 
-#define _GNU_SOURCE 1
-
 #ifdef HAVE_CONFIG_H
 #include "config.h"
 #endif