Don't appease clang static analyzer after all and roll back
the free(3) of mntbuf ... again. There's no point in doing
useless extra work when we're about to exit.

See also r240565.

Not reading file history:	uqs
Add const qualifier to the dst parameter of the ifnet if_output method.
On those machines that use critical(9) for counter(9) we need to
include systm.h.
Add usie to LINT.
Document constantness of dst argument to if_output.

Submitted by:	pluknet