87dac7da68
As suggested in https://github.com/llvm/llvm-project/issues/120, don't try to generate the extension file from clang, only do the linking step. Fixes the regression introduced in D74464 when running cmake inside the clang directory. Differential Revision: https://reviews.llvm.org/D74602
See docs/CMake.html for instructions on how to build LLVM with CMake.