Append EXTRA_CFLAGS to CFLAGS so that additional flags can be applied to
the compiler.

Acked-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>
Signed-off-by: Leo Yan <leo.yan@arm.com>
---
 tools/gpio/Makefile | 1 +
 1 file changed, 1 insertion(+)

diff --git a/tools/gpio/Makefile b/tools/gpio/Makefile
index 342e056c8c665ac075041ff7c7ca7ba94c691187..05a0057ec361626f41ca87e5295691364f03d2cb 100644
--- a/tools/gpio/Makefile
+++ b/tools/gpio/Makefile
@@ -17,6 +17,7 @@ endif
 MAKEFLAGS += -r
 
 override CFLAGS += -O2 -Wall -g -D_GNU_SOURCE -I$(OUTPUT)include
+override CFLAGS += $(EXTRA_CFLAGS)
 
 ALL_TARGETS := lsgpio gpio-hammer gpio-event-mon gpio-watch
 ALL_PROGRAMS := $(patsubst %,$(OUTPUT)%,$(ALL_TARGETS))

-- 
2.34.1