x86_64 is used as a baseline: the "x86_64" entry, whatever status it has,
is transformed into "all", and then the other entries in ARCHITECTURES
either dropped or rearranged appropriately.
* I'm leaving untested until we can test its functionality.
(builds fine on x86_64 though)
* This is pretty core and used by package kit, pkgman, etc.
* Needs to also go into haikuports.cross