updat Makefile

Signed-off-by: surenyi <surenyi82@163.com>

Makefile

@@ -38,6 +38,8 @@ endif
 cmsis_startup :=
 cmsis_srcs    :=
 objs          :=
+TARGET_CFLAGS :=
+TARGET_LDFLAGS:=
 
 CFLAGS += -I$(cmsis_dir)/inc \
 			 -I$(stdph_dir)/inc \
@@ -58,6 +60,7 @@ link_script ?= $(scripts_dir)/stm32f4x.lds
 iap_script  ?= iap.ld
 
 CFLAGS += -I$(target_dir)
+
 FP_FLAGS ?= -mfloat-abi=hard -mfpu=fpv4-sp-d16 -D__FPU_USED=1 -D__FPU_PRESENT=1
 
 ARCHCCVERSION = ${shell $(CC) -v 2>&1 | sed -n '/^gcc version/p' | sed -e 's/^gcc version \([0-9\.]\)/\1/g' -e 's/[-\ ].*//g' -e '1q'}
@@ -137,6 +140,7 @@ endif
 
 CFLAGS  += $(TARGET_CFLAGS)
 ASFLAGS += $(TARGET_CFLAGS)
+LDFLAGS += $(TARGET_LDFLAGS)
 
 cmsis_srcs += \
 	  $(cmsis_dir)/src/system_stm32f4xx.c