unix/unix_mphal: Add compile check for incompatible GIL+ASYNC_KBD_INTR.
unix/unix_mphal: Add compile check for incompatible GIL+ASYNC_KBD_INTR.

It is not safe to enable MICROPY_ASYNC_KBD_INTR and MICROPY_PY_THREAD_GIL
at the same time.  This will trigger a compiler error to ensure that it
is not possible to make this mistake.

pfalcon/micropython,pfalcon/micropython,pfalcon/micropython,pfalcon/micropython,pfalcon/micropython