Created attachment 743172 [details] build.log The configure phase fails with: CMake Error at cmake/modules/FindClang.cmake:118 (message): Could not find Clang builtin directory Call Stack (most recent call first): plugins/CMakeLists.txt:39 (find_package) I have the same issues with LLVM/Clang 12. I've had a look through the cmake files referenced but am not sure where it's going wrong. CMakeOutput.log contains nothing useful from what I see, but I'll attach it anyways. Cheers
Created attachment 743187 [details] CMakeOutput.log
Created attachment 743238 [details] emerge --info
Works after system reinstall