Because `mpthreadport.h` is included by `mpthread.h`.
Also remove unnecessary include of `mpthreadport.h` in esp32's `main.c`.
Signed-off-by: Damien George <damien@micropython.org>
This modifies the signature of mp_thread_set_state() to use
mp_state_thread_t* instead of void*. This matches the return type of
mp_thread_get_state(), which returns the same value.
`struct _mp_state_thread_t;` had to be moved before
`#include <mpthreadport.h>` since the stm32 port uses it in its
mpthreadport.h file.
This is to keep the top-level directory clean, to make it clear what is
core and what is a port, and to allow the repository to grow with new ports
in a sustainable way.