perform a version check before including physfs (maybe there is a better place for this?) and allow overriding automagic search
#! /usr/bin/sed -nf
s/^#define *FREETYPE_MAJOR *\([^ ][^ ]*\).*$/freetype_major="\1" ;/p
s/^#define *FREETYPE_MINOR *\([^ ][^ ]*\).*$/freetype_minor=".\1" ;/p
s/^#define *FREETYPE_PATCH *\([^ ][^ ]*\).*$/freetype_patch=".\1" ;/p