--- a/vmhgfs-fuse/fsutil.h
+++ b/vmhgfs-fuse/fsutil.h
@@ -29,6 +29,9 @@
 
 #include "request.h"
 #include "vm_basic_types.h"
+#ifndef _GNU_SOURCE
+#define _GNU_SOURCE
+#endif
 #include "hgfsProto.h"
 #include <fuse.h>
 
