To get from libpng.tar.gz to built library
------------------------------------------
0) Get archive

From: ftp://ftp.group42.com/pub/png/ or ftp://ftp.uu.net/graphics/png/

1) Extract archive
	mkdir Implementation
	cd Implementation
	gnutar xvfpz ../libpng*.tar.gz

2) Apply patch(es) to libpng source:

This may be needed to fix gamma rounding bug in 0.81
	patch < ../libpng-0.81-bugpatch

General patch for arena
	patch < ../libpng-arena-patch 

3) Build
	make libpng.a

