Lua 5.2 (but not earlier or later versions) have a powerpc platform detection check.
This check was not using the preferred define __powerpc__ so fails to trigger on gcc.
It also assumes that all of powerpc is big-endian.
Check a more universal preprocessor define, and add support for the upcoming FreeBSD PowerPC64LE.
Submitted by: Daniel Kolesa <firstname.lastname@example.org>