As mentioned in https://github.com/MarlinFirmware/Marlin/issues/9429#issuecomment-385305597



Co-Authored-By: Jack Bradach <jack@bradach.net>

Co-Authored-By: Bob-the-Kuhn <bob-the-kuhn@users.noreply.github.com>

Addressing #10569

From #10531

Co-Authored-By: chriscg9 <chriscg9@users.noreply.github.com>

…and any other platforms where `false`/`true` are defined as `0x0`/`0x1`.

This fixes issue #10550.

Raise an error when an unknown/unsupported G/M command is requires.

This will address #10546

…as with #10540

Co-Authored-By: per1234 <per1234@users.noreply.github.com>

Addressing #10538

As pointed out in #10532

on the STM32 platform

Based on #10519

Co-Authored-By: Alex <alex18881@users.noreply.github.com>

Followup to #10516

* AVR: Atomic bit set and clear

The critical section can be dropped, saving 3 cycles per access. Also simplified pin toggling for all ports.