Update Makefile

Author: dmazzella

ports/nrf/Makefile

@@ -208,6 +208,7 @@ ifeq ($(INTERNAL_LIBM),1)
 OBJ += $(addprefix $(BUILD)/, $(SRC_LIBM:.c=.o))
 endif
 OBJ += $(addprefix $(BUILD)/, $(SRC_S:.s=.o))
+OBJ += $(addprefix $(BUILD)/, $(SRC_MOD:.c=.o))
 
 $(BUILD)/$(FATFS_DIR)/ff.o: COPT += -Os
 $(filter $(PY_BUILD)/../extmod/vfs_fat_%.o, $(PY_O)): COPT += -Os