makefile: optimize for size

diff --git a/Makefile b/Makefile
index 9abe973..1ddb793 100644 (file)
--- a/Makefile
+++ b/Makefile
@@ -13,7 +13,7 @@ AVRSIZE = avr-size
 AVRDUDE = avrdude
 
 CPPFLAGS = -DF_CPU=$(F_CPU) -DBAUD=$(BAUD) -I.
-CFLAGS = -O -g -Wall
+CFLAGS = -Os -g -Wall
 CFLAGS += -funsigned-char -funsigned-bitfields -fpack-struct -fshort-enums
 
 LDFLAGS = -Wl,-Map,hbc.map