[CMake] Fix symlink refactor for multi-configuration generators

This fix, while a bit complicated, preserves the reusability while fixing the issues reported on llvm-commits with visual studio generators.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@288679 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed