2.21.5 (unstable):

   This release is a release candidate for 2.22.0.  As such, some unfinished
   API has been disabled (notably the network IO classes that we were not able
   to finish in time).  Also, a few documentation-related fixes.

   Daniel Elstner (5):
         Remove sigc from the Doxygen excluded symbols
         Sanitize the Glib::Cond usage example
         Officially deprecate GLIBMM_CHECK_PERL macro
         Delete obsolete MAINTAINERS file
         Implement Gio::Socket ctors using Gio::Initable

   Jonathon Jongsma (2):
         Add Network I/O classes to new documentation module
         disable network io stuff.  punt to next release