py/modmicropython: Add micropython.kbd_intr() function.

It controls the character that's used to (asynchronously) raise a
KeyboardInterrupt exception.  Passing "-1" allows to disable the
interception of the interrupt character (as long as a port allows such a
behaviour).

py/modmicropython.c

@@ -31,6 +31,7 @@
 #include "py/stackctrl.h"
 #include "py/runtime.h"
 #include "py/gc.h"
+#include "py/mphal.h"
 
 // Various builtins specific to MicroPython runtime,
 // living in micropython module
@@ -129,6 +130,14 @@ STATIC MP_DEFINE_CONST_FUN_OBJ_0(mp_micropython_heap_unlock_obj, mp_micropython_
 STATIC MP_DEFINE_CONST_FUN_OBJ_1(mp_alloc_emergency_exception_buf_obj, mp_alloc_emergency_exception_buf);
 #endif
 
+#if MICROPY_KBD_EXCEPTION
+STATIC mp_obj_t mp_micropython_kbd_intr(mp_obj_t int_chr_in) {
+    mp_hal_set_interrupt_char(mp_obj_get_int(int_chr_in));
+    return mp_const_none;
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_1(mp_micropython_kbd_intr_obj, mp_micropython_kbd_intr);
+#endif
+
 #if MICROPY_ENABLE_SCHEDULER
 STATIC mp_obj_t mp_micropython_schedule(mp_obj_t function, mp_obj_t arg) {
     if (!mp_sched_schedule(function, arg)) {
@@ -162,6 +171,9 @@ STATIC const mp_rom_map_elem_t mp_module_micropython_globals_table[] = {
     { MP_ROM_QSTR(MP_QSTR_heap_lock), MP_ROM_PTR(&mp_micropython_heap_lock_obj) },
     { MP_ROM_QSTR(MP_QSTR_heap_unlock), MP_ROM_PTR(&mp_micropython_heap_unlock_obj) },
     #endif
+    #if MICROPY_KBD_EXCEPTION
+    { MP_ROM_QSTR(MP_QSTR_kbd_intr), MP_ROM_PTR(&mp_micropython_kbd_intr_obj) },
+    #endif
     #if MICROPY_ENABLE_SCHEDULER
     { MP_ROM_QSTR(MP_QSTR_schedule), MP_ROM_PTR(&mp_micropython_schedule_obj) },
     #endif

py/mpconfig.h

@@ -445,7 +445,7 @@
 #   endif
 #endif
 
-// Whether to provide the mp_kbd_exception object
+// Whether to provide the mp_kbd_exception object, and micropython.kbd_intr function
 #ifndef MICROPY_KBD_EXCEPTION
 #define MICROPY_KBD_EXCEPTION (0)
 #endif