Build System: Enable use of ~/.asterisk.makeopts and /etc/asterisk.makeopts.

The Makefile claims that you can set default menuselect options by creating
~/.asterisk.makeopts or /etc/asterisk.makeopts, but they are never read.
The rule for menuselect.makeopts is only allowed to run if the active target
is 'menuselect', but the menuselect target doesn't depend on
menuselect.makeopts.  A dot (wildcard character) was added so the rule will
be active for the targets that cause it to run: nmenuselect, cmenuselect,
and gmenuselect.

ASTERISK-13271 #close
Reported by: John Nemeth

Change-Id: Ibde804ff196283def49ccb9432fbf224a22586e2