If we include this file, it generates inline assembly, which would be fine
except that when apps are being built with bitcode, that isn't allowed.
rdar://103274667
Upstream build system zippering support.
Setting the `SWIFT_ENABLE_MACCATALYST` flag will build the compatibility
libraries with zippering enabled.
Note that AppleClang and LLVM Clang use different flags to write
zippered files. The Swift stdlib build doesn't know what clang we're
using, so we can't ask it for the compiler ID to determine which whether
we're using AppleClang or LLVM clang, hence the nasty `execute_process`
trick to figure out whether the compiler that's actually compiling the
stdlib knows about the flag or not.