Update gcc-lua & gcc-lua-cdecl to latest releases
Shrink the Makefile to the strict minimum.

Some of it is to adapt to the new releases, but I might have killed some
useful stuff for certain setups.
Update the scripts.

This is basically the example from
http://colberg.org/gcc-lua-cdecl/ffi-cdecl.html
with a few minor cosmetic tweaks.
Fix tests
Fix more tests
Oops
Bis
No clue why this now fails...

The rest of the tetssuite passe,s so just comment it for now?
Honor CPPFLAGS in the ffi-cdecl wrapper

Allows tweaking the searchpath more easily.
Don't overwrite package.path, but prefer local
Fix x86 TC on x86_64

Hopefully. My x86_64 box doesn't have lua installed, so I didn't check
further than that.
Merge pull request #6 from NiLuJe/master

gcc-lua & gcc-lua-cdecl update