neverball: add patch for libpng-1.6 from pkgsrc.

srcpkgs/neverball/patches/share_base__image.c.patch

@@ -0,0 +1,13 @@
+$NetBSD: patch-share_base__image.c,v 1.1 2013/02/26 11:16:19 joerg Exp $
+
+--- share/base_image.c.orig	2013-02-25 20:30:28.000000000 +0000
++++ share/base_image.c
+@@ -94,7 +94,7 @@ static void *image_load_png(const char *
+         default: longjmp(png_jmpbuf(readp), -1);
+         }
+ 
+-        if (!(bytep = png_malloc(readp, h * png_sizeof(png_bytep))))
++        if (!(bytep = png_malloc(readp, h * sizeof(*bytep))))
+             longjmp(png_jmpbuf(readp), -1);
+ 
+         /* Allocate the final pixel buffer and read pixels there. */