[PATCH] [compiler-rt] Make compiler-rt tests work with relocatable SDKs on OS X

[Alexander Potapenko]

I like this more. There's yet another option which I ended up with when I've encountered this problem on our OSX bot that bootstraps Clang.
It is to run:

  cd ${LLVM_BINARY_DIR} && make -C ${LLVM_CHECKOUT}/projects/libcxx installheaders HEADER_DIR=${PWD}/include

, which installs the libcxx headers from the Clang checkout for of the newly built Clang.

http://reviews.llvm.org/D4047