don't warn if xi is explicitely turned off
don't warn if xi is explicitely turned off

darcs-hash:20080724211320-a887e-4ff34e32e51c57e1831213e32026d458d6cf2091.gz

RaphaelRochet/easystroke,RaphaelRochet/easystroke,thjaeger/easystroke,thjaeger/easystroke