[CMake] Allow LLVM to be embedded and built in a subfolder as part of another project.

Patch by Bertrand Bellenot!

Reviewed by Chris Bieneman and me.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@272481 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed