Windows 10, 1.8.19 version. Trying to upload to an ESP board.
Error message:
exit status 1
'LED_BUILTIN' was not declared in this scope.
The ESP core that you are using does not have a #define for LED_BUILTIN
Either #define it yourself using the pin number that your LED is attached to or declare a variable with a suitable name such as myLED with the value of your LED pin and use that instead of LED_BUILTIN or replace all references to LED_BUILTIN in the sketch with the pin number that yor LED is attached to