New OSX build prior to RT5 Release

From what I understand OS X tools I’ve got has clang already and not gcc. Do I need to have a clang 3.7 built before building RT since clang is already there? Also, do I need the real gcc as it is listed in linux dependencies Linux - RawPedia . I tend to infer it’s requirement by these instructions. MacOS - RawPedia The clang and gcc pieces cause problems on my system.

$clang --version
Apple LLVM version 8.0.0 (clang-800.0.42.1)
Target: x86_64-apple-darwin15.6.0
Thread model: posix