[CMake] Refactor add_llvm_implicit_projects to be reusable

This adds llvm_add_implicit_projects which takes a project name and is wrapped by add_llvm_implicit_projects.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@262948 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed