Enable link map file generation.

stm/Makefile

@@ -31,7 +31,7 @@ else
 CFLAGS += -Os -DNDEBUG
 endif
 
-LDFLAGS = --nostdlib -T stm32f405.ld
+LDFLAGS = --nostdlib -T stm32f405.ld -Map=$(@:.elf=.map) --cref
 LIBS =
 
 # uncomment this if you want libgcc

unix/Makefile

@@ -12,7 +12,7 @@ include ../py/py.mk
 
 # compiler settings
 CFLAGS = -I. -I$(PY_SRC) -Wall -Werror -ansi -std=gnu99 -DUNIX $(CFLAGS_MOD)
-LDFLAGS = $(LDFLAGS_MOD) -lm
+LDFLAGS = $(LDFLAGS_MOD) -lm -Wl,-Map=$@.map,--cref
 
 ifeq ($(MICROPY_MOD_TIME),1)
 CFLAGS_MOD += -DMICROPY_MOD_TIME=1