[CMake] Put headers relative to clang

When libcxx isn't building with an installed LLVM we copy the libcxx headers into the LLVM build directory so that a clang in that build tree can find the headers relative to itself.

This is only important in situations where you don't have headers installed under /, which is common these days on Darwin.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@289963 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed