message: Fix project.cc unit tests.
  x processing broke.
diff: @@ -190,7 +190,7 @@ Project::Entry GetCompilationEntryFromCompileCommandEntry(
  // Clang does not have good hueristics for determining source language, we
  // should explicitly specify it.
  if (auto source_file_type = SourceFileType(entry.file)) {
  - if (AnyStartsWith(result.args, "-x")) {
  + if (!AnyStartsWith(result.args, "-x")) {
  result.args.push_back("-x" + *source_file_type);
  }
  if (!AnyStartsWith(result.args, "-std=")) {
  