Homebrew/homebrew — pull request #31864 by jacknagel (2014-08-25 04:31:53+00:00)
Title: Revert "libsigc++ 2.3.1"

2.3.x is a development branch, like other gnome-affiliated software, so we should really still be on 2.2.x.

Need to check library compatibility but it seems OK at first glance.