Handle the removal of embedded libpng from upstream-svn.
Index: navit/configure.in
===================================================================
--- navit.orig/configure.in	2010-01-17 03:33:12.435215128 +0100
+++ navit/configure.in	2010-01-17 03:33:15.418553637 +0100
@@ -874,7 +874,6 @@
 navit/speech/speech_dispatcher/Makefile
 navit/support/Makefile
 navit/support/espeak/Makefile
-navit/support/libpng/Makefile
 navit/vehicle/Makefile
 navit/vehicle/android/Makefile
 navit/vehicle/file/Makefile
