revert CFLAGS change

Author: jepler

ports/raspberrypi/Makefile

@@ -215,7 +215,7 @@ endif
 # Remove -Wno-stringop-overflow after we can test with CI's GCC 10. Mac's looks weird.
 DISABLE_WARNINGS = -Wno-stringop-overflow -Wno-unused-function -Wno-unused-variable -Wno-strict-overflow -Wno-cast-align -Wno-strict-prototypes -Wno-nested-externs -Wno-double-promotion -Wno-sign-compare
 
-CFLAGS += $(INC) -Wall -Werror -std=gnu11 -nostdlib -fshort-enums $(BASE_CFLAGS) $(CFLAGS_MOD) $(COPT) $(DISABLE_WARNINGS) -Werror=missing-prototypes -Wno-error=unused-result
+CFLAGS += $(INC) -Wall -Werror -std=gnu11 -nostdlib -fshort-enums $(BASE_CFLAGS) $(CFLAGS_MOD) $(COPT) $(DISABLE_WARNINGS) -Werror=missing-prototypes
 
 CFLAGS += \
   -march=armv6-m \