use err.h for warn() prototype.  i don't see the problem stated in the comment any longer (backout if i'm wrong).
use err.h for warn() prototype.  i don't see the problem stated in the
comment any longer (backout if i'm wrong).

MarginC/kame,MarginC/kame,MarginC/kame,MarginC/kame,MarginC/kame,MarginC/kame,MarginC/kame