message: x c++-header has implicit -std=c++14
diff: @@ -154,7 +154,7 @@ Project::Entry GetCompilationEntryFromCompileCommandEntry(
  if (!AnyStartsWith(entry.args, "-std=")) {
  if (*source_file_type == "c")
  result.args.push_back("-std=gnu11");
  - else if (*source_file_type == "c++")
  + else if (*source_file_type == "c++" || *source_file_type == "c++-header")
  result.args.push_back("-std=c++14");
  }
  }
  