Remove $FreeBSD$: one-line .c comment pattern

Remove /^/[*/]\s*\$FreeBSD\$.*\n/

Improve blacklist support before upgrading libblacklist

The locally declared enum of blacklistd actions needs to be
hidden when the soon to be committed changes to libblacklist
are brought into the tree. Fix the type of the "msg" parameter
to match the library.

There should be no functional changes.

MFC after: 3 days
Sponsored by: The FreeBSD Foundation

Revisit blacklistd support in ftpd

Enhance blacklistd support to not log anything by default,
unless blacklistd support is enabled on the command line.
Document new flag in man page, cleanup patches to be less
intrusive in code.

Reported by: Rick Adams
Reviewed by: cem, emaste
MFC after: 1 week
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D8374

Update blacklist support in ftpd to clarify fd usage

The ftp daemon dups the control socket to stdin and uses that fd
throughout the code. Clarify this usage slightly by changing from
explicit use of "0" for the fd to a variable, to make it clear what
the zero represents in the non-blacklist code. Make the
blacklist_notify routine use STDIN_FILENO so as to have less of a
"magic number" feel to the code.

Reviewed by: cem
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D6716

Add blacklist support to ftpd

Reviewed by: rpaulo
Approved by: rpaulo
Relnotes: YES
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D6703