This imports certain files from libaemu into gfxstream
guest.
Some are quite specific to gfxstream (Stream, ring_buffer) and others
we expect to Mesa-ify with time (AlignedBuf, Allocator) [probably
while keeping some C++ interface].
The main benefit of importing is easier refactoring and packaging.
Reviewed-by: Aaron Ruby <aruby@blackberry.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/32062>
