[compiler-rt] r227509 - [compiler-rt] OS X: Update the CMake and Make builds to explicitely use libc++, mmacosx-version-min and SDKs

[Justin Bogner]

Kuba Brecka <kuba.brecka at gmail.com> writes:
> But the Command Line Tools do contain the SDK, right? What is the
> command to get the path to it then?

I think the simplest thing to do is to not provide a -isysroot if we
don't find an SDK for OSX. On a system without Xcode an empty string is
returned from `xcrun --sdk macosx --show-sdk-path`, whereas on a system
with Xcode the result matches `xcodebuild -version -sdk macosx Path`.