diff --git a/Makefile b/Makefile
index 213be43..8ff9359 100644
--- a/Makefile
+++ b/Makefile
@@ -42,7 +42,7 @@ FUSES      = -U hfuse:w:0xd2:m -U lfuse:w:0xff:m
 # Tune the lines below only if you know what you are doing:
 
 AVRDUDE = avrdude $(PROGRAMMER) -p $(DEVICE) -B 10 -F
-COMPILE = avr-gcc -Wall -Os -DF_CPU=$(CLOCK) -mmcu=$(DEVICE) -I. -ffunction-sections --std=c99
+COMPILE = avr-gcc -Wall -Os -DF_CPU=$(CLOCK) -mmcu=$(DEVICE) -I. -ffunction-sections
 
 # symbolic targets:
 all:	grbl.hex
@@ -97,4 +97,3 @@ cpp:
 
 # include generated header dependencies
 -include $(OBJECTS:.o=.d)
-