diff --git a/src/hb-blob.cc b/src/hb-blob.cc
index f09526659..c1ed0f2a7 100644
--- a/src/hb-blob.cc
+++ b/src/hb-blob.cc
@@ -25,11 +25,6 @@
  * Red Hat Author(s): Behdad Esfahbod
  */
 
-/* http://www.oracle.com/technetwork/articles/servers-storage-dev/standardheaderfiles-453865.html */
-#ifndef _POSIX_C_SOURCE
-#define _POSIX_C_SOURCE 200809L
-#endif
-
 #include "hb.hh"
 #include "hb-blob.hh"
 
diff --git a/src/hb.hh b/src/hb.hh
index 631592def..cfe6d68fb 100644
--- a/src/hb.hh
+++ b/src/hb.hh
@@ -35,6 +35,10 @@
 #include "config.h"
 #endif
 
+#ifndef _POSIX_C_SOURCE
+#define _POSIX_C_SOURCE 200809L
+#endif
+
 #include "hb.h"
 #define HB_H_IN
 #ifdef HAVE_OT