-O2 in new avr-gcc makes too big a bootloader to fit on 328(and 328p)

Author: iMartyn

hardware/arduino/avr/bootloaders/atmega/Makefile

@@ -48,7 +48,7 @@ STK500-2 = $(STK500) -d$(MCU_TARGET) -ms -q -lCF -LCF -cUSB -I200kHz -s -wt
 
 
 OBJ        = $(PROGRAM).o
-OPTIMIZE   = -O2
+OPTIMIZE   = -Os
 
 DEFS       = 
 LIBS       =