add the directories EGL/GLES headers will be installed to

ok matthieu@

src/etc/mtree/BSD.x11.dist

@@ -1,4 +1,4 @@
-#       $OpenBSD: BSD.x11.dist,v 1.28 2012/10/06 17:44:52 shadchin Exp $
+#       $OpenBSD: BSD.x11.dist,v 1.29 2013/08/22 09:49:51 jsg Exp $
 
 /set type=dir uname=root gname=wheel mode=0755
 .
@@ -33,6 +33,16 @@
                     internal
                     ..
                 ..
+                EGL
+                ..
+                GLES
+                ..
+                GLES2
+                ..
+                GLES3
+                ..
+                KHR
+                ..
                 X11
                     ICE
                     ..