diff --git a/bare-arm/Makefile b/bare-arm/Makefile
index 6ee85526285dd3e6ec870411ad9d78a6c9a15232..cfd427c609249fbfffb1a3f649ffb88f6cf84aff 100644
--- a/bare-arm/Makefile
+++ b/bare-arm/Makefile
@@ -13,7 +13,7 @@ INC += -I..
 INC += -I$(BUILD)
 
 CFLAGS_CORTEX_M4 = -mthumb -mtune=cortex-m4 -mabi=aapcs-linux -mcpu=cortex-m4 -mfpu=fpv4-sp-d16 -mfloat-abi=hard -fsingle-precision-constant -Wdouble-promotion
-CFLAGS = $(INC) -Wall -Werror -std=gnu99 -nostdlib $(CFLAGS_CORTEX_M4) $(COPT)
+CFLAGS = $(INC) -Wall -Werror -std=c99 -nostdlib $(CFLAGS_CORTEX_M4) $(COPT)
 
 #Debugging/Optimization
 ifeq ($(DEBUG), 1)