message: Use raw module format to fix -gmodules crash
  To avoid `llvm::report_fatal_error("unknown module format")` in getPCHContainerWriter.
  See
diff: @@ -175,6 +175,8 @@ buildCompilerInvocation(const std::string &main, std::vector<const char *> args,
  ci->getPreprocessorOpts().ImplicitPCHInclude.clear();
  ci->getPreprocessorOpts().PrecompiledPreambleBytes = {0, false};
  ci->getPreprocessorOpts().PCHThroughHeader.clear();
  +
  + ci->getHeaderSearchOpts().ModuleFormat = "raw";
  return ci;
  }
  