LOGF/LOGF_COLOR always ran fmt::sprintf even when the output was discarded; at
emulator log volume the formatting alone costs frames. Add Log::IsSilent() and
short-circuit before formatting. Behavior-preserving on all platforms (it only
skips work whose result is thrown away); before init it reports non-silent so
early logs still print.
(cherry picked from commit 1749e0fc68ae4290055fb12f72c9bb4baf466190)
macOS compiles the existing POSIX/Linux code paths (KYTY_PLATFORM_LINUX)
targeting x86_64 under Rosetta 2. Adds an APPLE branch to the build:
selects Apple's ld64 linker, unsets the Ninja response-file forcing (Apple
ar has no @file support), derives the target arch from CMAKE_OSX_ARCHITECTURES
for cpuinfo/ffmpeg, and re-signs the binary post-build with JIT entitlements
(required to execute written trampolines and Rosetta-translated guest code).
All changes are guarded by if(APPLE); Windows and Linux configuration is
unchanged.
(cherry picked from commit 13be13b7573b9a687cf87531a81e4497ed3de1d5)