mimxrt: Enable frozen modules.

ports/mimxrt/Makefile

@@ -15,6 +15,9 @@ include $(BOARD_DIR)/mpconfigboard.mk
 QSTR_DEFS = qstrdefsport.h
 QSTR_GLOBAL_DEPENDENCIES = $(BOARD_DIR)/mpconfigboard.h
 
+# MicroPython feature configurations
+FROZEN_MANIFEST ?= boards/manifest.py
+
 # Include py core make definitions
 include $(TOP)/py/py.mk
 

ports/mimxrt/boards/manifest.py

@@ -0,0 +1 @@
+freeze("$(PORT_DIR)/modules")

ports/mimxrt/mpconfigport.h

@@ -48,6 +48,8 @@
 #define MICROPY_ENABLE_SOURCE_LINE          (1)
 #define MICROPY_ERROR_REPORTING             (MICROPY_ERROR_REPORTING_TERSE)
 #define MICROPY_CAN_OVERRIDE_BUILTINS       (1)
+#define MICROPY_MODULE_FROZEN_MPY           (1)
+#define MICROPY_QSTR_EXTRA_POOL             mp_qstr_frozen_const_pool
 
 // Control over Python builtins
 #define MICROPY_PY_BUILTINS_STR_COUNT       (0)