This moves the CPU feature querying to the frontend. The primary purpose
here is for the wow64 frontend to not require linux-isms for querying
these features. This is required since non-Linux environments don't have
the "CPUID" feature for reading EL1 MSRs in EL0.
Wiring up the remaining wow64 registry querying is left for a future
exercise.
This also technically removes an xbyak requirement from FEXCore for when
building the x86 Test harness runner, but that doesn't really matter for
regular use cases.
Forces disabling use of __attribute__((preserve_all)).
Until CI uses clang17, where this attribute was added, instcountci fails
when FEX is compiled with clang>=17.
This is blocking performance improvements. This backend is almost
unilaterally unused except for when I'm testing if games run on Radeon
video drivers.
Hopefully AmpereOne and Orin/Grace can fulfill this role when they
launch next year.
It is not an external component, and it makes paths needlessly long.
Ryan seemed amenable to this when we discussed on IRC earlier.
Signed-off-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
