--- old/src/java.base/unix/classes/sun/nio/fs/UnixConstants.java.template	2016-09-29 14:26:27.902927335 -0700
+++ new/src/java.base/unix/classes/sun/nio/fs/UnixConstants.java.template	2016-09-29 14:26:27.795927334 -0700
@@ -27,6 +27,8 @@
 
 @@END_COPYRIGHT@@
 
+#define _GNU_SOURCE
+
 #include <stdio.h>
 #include <errno.h>
 #include <unistd.h>
@@ -55,6 +57,7 @@
     static final int PREFIX_O_EXCL = O_EXCL;
     static final int PREFIX_O_TRUNC = O_TRUNC;
     static final int PREFIX_O_SYNC = O_SYNC;
+    static final int PREFIX_O_DIRECT = O_DIRECT;
 
 #ifndef O_DSYNC
     // At least FreeBSD doesn't define O_DSYNC