Fix typos on LLVM.cmake. Export LLVM_ON_UNIX & LLVM_ON_WIN32.

Patch by arrowdodger!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@128789 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed