meta-comment { not using default arguments here because transpiler bugs in this case }

ifdef NoNanoHTTPD
static virtual NanoHTTPD.Response serve404() {
  ret subBot_serve404();
}
static virtual NanoHTTPD.Response serve404(S msg) {
  ret subBot_serve404(msg);
}
endifdef

ifndef NoNanoHTTPD
static NanoHTTPD.Response serve404() {
  ret serve404("Not found");
}
static NanoHTTPD.Response serve404(S msg) {
  ret NanoHTTPD.newFixedLengthResponse(NanoHTTPD.Status.NOT_FOUND, NanoHTTPD.MIME_PLAINTEXT, "Code 404 - " + msg);
}
endifndef