Do not set urgency if windows is focused

[Renato Botelho]

Recently I back to use FreeBSD as my primary desktop and noted something
that was annoying me, urxvt was setting urgency hint even if windows is
focused.

Just to clarfy, in this case I use urxvt to run my IRC/XMPP client,
weechat, and every time a new private message or my name is noted on a
group conversation, weechat send a bell and urxvt, that has urgentOnBell
set to true, set urgency hint so I can be notified about it. But, when
I'm having a private conversation with someone, it keeps setting urgency
on evey single message comes.

After dig a little bit I've found this patch [1] on gentoo portage and I
would like to check here if you believe this is an acceptable change.

If you prefer, I can write a patch to add it as a new option, then user
can chose what he wants, something like urgentOnBellFocused, default to
true to keep current behavior.

Thoughts?

[1]
https://gitweb.gentoo.org/repo/gentoo.git/tree/x11-terms/rxvt-unicode/files/rxvt-unicode-9.06-no-urgency-if-focused.diff