Removing libpng from ext and removed the libpng build command from the ext build target. Added the -DPNG_SKIP_SETJMP_CHECK flag to the linux2-config.py build config file. This should allow users to use their local copy of libpng rather than relying on the libpng in ext. Users should probably clean out their <fife>/etc/install/* directories and re-run 'scons ext'. Tested on ubuntu 10.04

prefix=@prefix@
exec_prefix=${prefix}
libdir=@libdir@
includedir=${prefix}/include

Name: guichan
Description: A portable C++ GUI library designed for games using Allegro, HGE, OpenGL, OpenLayer and/or SDL.
Version: @VERSION@
Requires: sdl
Conflicts:
Libs: -L${libdir} -lguichan_sdl
Cflags: -I${includedir}