Attached you'll find updated version of Pixel's patch for ocaml compiler
to warn about unused local variables. I also made it regular option with
possibility of turning it on/off (off is default).

BTW: what stops this patch from going upstream?

-- 
: Michal Moskal :: http://www.kernel.pl/~malekith : GCS {C,UL}++++$ a? !tv
: When in doubt, use brute force. -- Ken Thompson : {E-,w}-- {b++,e}>+++ h