makefile: add cflag difference check

This should eliminate occasional inconsisten builds caused by switching between 'make wizard TILES=y' and 'make wizard', and other such bad combination switches.

Signed-off-by: Steven Noonan <steven@uplinklabs.net>

Created by  Steven Noonan  on October 31, 2009
QV3TDY7PQZUC3Q35OQWF6OBR7JMH663VNNEJXXF3Y5RC6V5PY2SQC
Change contents