Add pidfile support to ggated(8)

[ngie]

Summary

Add pidfile support to ggated(8)

The tests will manipulate the system daemon today, which can cause undesired
service interruption when run.

This change allows the geom_gate tests to be run with an arbitrary ggated(8)
daemon / geom_gate(4) device pairing.

• Sort #includes
• Use a more common idiom for parsing options with getopt(3)

MFC after: 1 week
Sponsored by: EMC / Isilon Storage Division

Test Plan

I've been using this version with the tests in
^/user/ngie/more-tests2/tests/sys/geom/class/geom_gate for some time
successfully

[bjk]

sbin/ggate/ggated/ggated.8

94

Spurious leading .El, I think.

[ngie]

sbin/ggate/ggated/ggated.8

94

mandoc -Tlint agrees -- thanks !

[ngie]

Remove spurious .El in ggated(8)

Reported by: bjk

[ngie]

Ping?

[bjk]

The man page also needs to update .Dd, sorry I missed that before.
(Still too busy to look at the code itself.)

[ngie]

In D4836#104404, @bjk wrote:

The man page also needs to update .Dd, sorry I missed that before.
(Still too busy to look at the code itself.)

Done.

[ngie]

Committed in rS294973.