$OpenBSD: patch-configure_ac,v 1.1 2011/07/08 20:38:00 naddy Exp $

Fix build with png-1.5.

--- configure.ac.orig	Thu Jul  7 09:20:30 2011
+++ configure.ac	Thu Jul  7 09:20:51 2011
@@ -952,7 +952,7 @@ AM_CONDITIONAL(USE_JPEG, test "x$support_jpeg" = "xyes
 if test "x$support_png" = "xyes"; then
     AC_CHECK_LIB(
         png,
-        png_check_sig,
+        png_sig_cmp,
         [],
         [support_png=no],
         [-lz -lm]