gsocket: Fix build error on Android
gsocket: Fix build error on Android

imr_interface.s_addr is not defined in the HAVE_IP_MREQN case.

https://bugzilla.gnome.org/show_bug.cgi?id=740791

endlessm/glib,endlessm/glib,endlessm/glib,endlessm/glib,endlessm/glib