Initialize xgselect in function xg_select when gfds_size == 0.

Initialize xgselect in function xg_select when gfds_size == 0.

Emacs should no longer hang when using newer versions of GLib
(initially reported against libglib2.0-0 2.32.0-2).

Origin: http://pkgs.fedoraproject.org/gitweb/?p=emacs.git;a=commitdiff;h=a2302b156dba1cc136e8363605d78a66eb3a92a6
Bug: http://debbugs.gnu.org/cgi/bugreport.cgi?bug=9754
Bug-Red-Hat: https://bugzilla.redhat.com/show_bug.cgi?id=711739
Bug-Debian: http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=666691
Applied-Upstream: Fixed in Emacs 24