[compiler-rt] Enable building 16 bit floating point builtins in apple platforms if supported by the compiler (PR #84192)

[Gabriel Baraldi via llvm-commits]

gbaraldi wrote:

The use case here was that if someone was using a recent clang to build Julia, it would try to use the new types and blow up. 

https://github.com/llvm/llvm-project/pull/84192