x11/x11vnc patch

[Cherry G. Mathew <cherry%zyx.in@localhost>]

Fixes -lpng build link failure.

TIA
-- 
~cherry

Index: x11/x11vnc/Makefile
===================================================================
RCS file: /cvsroot/pkgsrc/x11/x11vnc/Makefile,v
retrieving revision 1.65
diff -u -r1.65 Makefile
--- x11/x11vnc/Makefile 9 Jan 2017 08:07:54 -0000       1.65
+++ x11/x11vnc/Makefile 1 Feb 2017 08:32:42 -0000
@@ -28,6 +28,7 @@

 .include "../../security/openssl/buildlink3.mk"
 .include "../../net/libvncserver/buildlink3.mk"
+.include "../../graphics/png/buildlink3.mk"
 .include "../../sysutils/desktop-file-utils/desktopdb.mk"
 .include "../../mk/pthread.buildlink3.mk"
 .include "../../mk/bsd.pkg.mk"