Merge pull request #29 from sabetts/for-rpav

add *c2ffi-program*
make find-local-spec handle a pathname with a device component

Without this fix, it fails to load specs in paths like z:/src/sdl2/src/specs/
use CFFI:FOREIGN-POINTER in PTR function.
Merge pull request #30 from sabetts/windows-bugs

Allegro CL bugs
use cffi:foreign-pointer instead of (type-of (cffi:null-pointer))