Remove $FreeBSD$: one-line sh pattern

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

lualoader: fix lua-lint run

luacheck rightfully complains that i is unused in the show-module-options
loop at the end (it was used for some debugging in the process).

We've added a new pager module that's compiled in, so declare that as an
acceptable global.

lua-lint: Hint that try_include is now an accepted global

try_include was added in r331563.

lua-lint: Whitelist cli_execute_unparsed as a global

Add --globals printc to lua-lint

We provide a global 'printc' as of r330282; make luacheck aware of this fact
so that we can use it without complaints.

lua-lint: Add note about luacheck in ports, silence warning

luacheck was added in ports r462609.

Silence warning about cli_execute -- it's non-standard, but for our setup it
will be a standard global.

Add script for linting stand/lua to tools/boot.

We require some --globals due to custom loader extensions in our
environment. Add everything required for this to tools/boot so that other
interested parties can get up and go with linting our scripts and not get a
bunch of false-positives.