unix/dev: Enable sys.maybe_intern().
#define MICROPY_CAN_OVERRIDE_BUILTIN_NAMESPACES (1)
#define MICROPY_PY_SYS_GETSIZEOF (1)
#define MICROPY_PY_SYS_INTERN (1)
+#define MICROPY_PY_SYS_MAYBE_INTERN (1)
#define MICROPY_PY_SYS_ROPROXY (1)
#define MICROPY_PY_SYS_STDFILES_OVERRIDE (1)
#define MICROPY_PY_MATH_FACTORIAL (1)
