After defining MENU_DEBUG project doesn't compile for ESP32

[ScruffR]

I need to debug the library but cannot get it to compile on my Adafruit HUZZAH32 Feather.

I first had this

#define ARDUINO_STREAMING           // import: Streaming library (v6.1.1)
#define MENU_DEBUG
#define MENU_DEBUG_OUT Serial

Which threw some errors

.../itemsTemplates.hpp:149:42: error: 'endl' was not declared in this scope
     _trace(Serial<<"toggle sysHandler!"<<endl;);

so I added

#define endl           "\r\n"

which got rid of the above error but ended up failing to link due to errors like these

undefined reference to `Menu::print_P(Print&, char const*, short)'
undefined reference to `Menu::operator<<(Print&, bool)'

(in multiple functions)