[llvm] [ADT] Use CMake to detect host endianness (NFC) (PR #164054)

[Kazu Hirata via llvm-commits]

kazutakahirata wrote:

> Is this compatible with bazel? I know the support level is much lower than cmake, but maybe worth checking that they can do something sensible here.

Yes.  For bazel, `config.h` is a static file, and `#defines` are hardcoded, supplied locally with some macro tricks, or from the command line `-DFOO=BAR`.


https://github.com/llvm/llvm-project/pull/164054