al_make_path_canonical
bool al_make_path_canonical(ALLEGRO_PATH *path)
Introduced in 5.0.0
Removes any leading '..' directory components in absolute paths. Removes all '.' directory components.
Note that this does not collapse "x/../y" sections into "y". This is by design. If "/foo" on your system is a symlink to "/bar/baz", then "/foo/../quux" is actually "/bar/quux", not "/quux" as a naive removal of ".." components would give you.
Examples: ex_path, ex_path_test
Most helpful discussions: