Minor
diff --git a/src/hb-blob.cc b/src/hb-blob.cc
index bbbc936..3ca50fb 100644
--- a/src/hb-blob.cc
+++ b/src/hb-blob.cc
@@ -25,7 +25,7 @@
  */
 
 /* http://www.oracle.com/technetwork/articles/servers-storage-dev/standardheaderfiles-453865.html */
-#define _POSIX_C_SOURCE 3
+#define _POSIX_C_SOURCE 199309L
 
 #include "hb-private.hh"