Nothing currently uses it on-tree.
Only known user, "unknown-horizons", is broken on-tree, upstream is
porting the game to Godot, and considers current engine "dead".
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.
Note that due to the way that cython extensions are built, this actually
uses the enet sources. They are pulled in via a second source archive
and then symlinked into place for the pyenet build to pick them up.
