[clang] [compiler-rt] [llvm] [SystemZ] Add support for half (fp16) (PR #109164)

[Ulrich Weigand via llvm-commits]

uweigand wrote:

> I see a lot of target specific pre-processing in clear_cache.c that either disables this to a no-op, or does something target specific. The test itself this is disabled for some targets. Seems reasonable to leave this as unsupported and disable the test (for now?). Also disabling enable_execute_stack_test.c.

Both clear_cache and enable_execute_stack should just be empty no-op functions on our platform.

https://github.com/llvm/llvm-project/pull/109164