codal_port: Enable MICROPY_STACK_CHECK to check C stack depth.

Author: dpgeorge

src/codal_port/main.c

@@ -48,7 +48,7 @@ void microbit_pyexec_file(const char *filename);
 
 void mp_main(void) {
     mp_stack_ctrl_init();
-    mp_stack_set_limit(8 * 1024);
+    mp_stack_set_limit(8 * 1024 - 512); // include 512 byte buffer zone for overflow
 
     for (;;) {
         microbit_system_init();

src/codal_port/mpconfigport.h

@@ -47,6 +47,7 @@
 #define MICROPY_VM_HOOK_LOOP                    MICROPY_VM_HOOK_POLL
 #define MICROPY_VM_HOOK_RETURN                  MICROPY_VM_HOOK_POLL
 #define MICROPY_ENABLE_GC                       (1)
+#define MICROPY_STACK_CHECK                     (1)
 #define MICROPY_KBD_EXCEPTION                   (1)
 #define MICROPY_HELPER_REPL                     (1)
 #define MICROPY_REPL_AUTO_INDENT                (1)