Make clean was seeing a "RM" linux command, so with this I'm trying to set OS to windows. not working though

Author: Pete Lewis

sparkfun/avr/bootloaders/optiboot/Makefile

@@ -24,10 +24,10 @@ PROGRAM    = optiboot
 # Arduino user IDE setup, or the Arduino source tree.
 # Uncomment this next lines to build within the arduino environment,
 # using the arduino-included avrgcc toolset (mac and pc)
-# ENV ?= arduino
+ENV ?= arduino
 # ENV ?= arduinodev
 # OS ?= macosx
-# OS ?= windows
+OS ?= windows
 
 
 # enter the parameters for the avrdude isp tool