2.55.2: (unstable):
Distro packagers should probably not package this yet.

Glib:
* IOCondition: Add an IO_ prefix to the enumerator names
  (Kjell Ahlstedt)
* TimeoutSource: Use monotonic time consistently
  (Kjell Ahlstedt) Bug #792524 (Dainis Jonitis)
* Source: Remove get_current_time().
  (Kjell Ahlstedt)
* KeyFile, OptionContext, Regex: Add exception specs to errthrow.
  (Kjell Ahlstedt)
* ustring:
  - Replace 8×format() with 1 variadic template.
  - Replace 9×compose() with 1 variadic template.
  - Use std::initializer_list instead of pointer + size
  (Daniel Boles) Bug #784211
* VariantBase:
  - Add operator==() and operator!=().
  (Kjell Ahlstedt) Bug #789330 (Daniel Boles)
  - cast_dynamic(): Remove noexcept(false).
  (Kjell Ahlstedt)

Glib::Gio:
* AppInfo: Update the name of the AppLaunchContext parameters
  (Kjell Ahlstedt)
* Action: Add exception specs to errthrow.
  (Kjell Ahlstedt)
* Application: Fix property_resource_base_path()'s type
  (Kjell Ahlstedt)
* Credentials, et al.: Add exception specs to errthrow.
  (Kjell Ahlstedt)
* DataInputStream:
  - Remove read_until*().
  - Fix the documentation of read_line_utf8().
  (Kjell Ahlstedt)
* InetSocketAddress, ProxyAddress: No guint16 in _WRAP_PROPERTY().
  (Kjell Ahlstedt)
* Settings: set_int() and friends shall return bool.
  (Kjell Ahlstedt) Bug #784211
* TlsClientConnection: Remove get/set/property_use_ssl3().
  (Kjell Ahlstedt)

gmmproc:
* Warn if parameter lists are not compatible
  (Kjell Ahlstedt)
* _WRAP_METHOD: Accept optional list of exceptions in errthrow
  (Kjell Ahlstedt)
* _WRAP_METHOD_DOCS_ONLY: Optionally suppress @return section.
  (Kjell Ahlstedt) Bug #787978
* docextract_to_xml.py: Add --exclude-file option.
  (Kjell Ahlstedt)
* Suppress the @return section if return type is void.
  (Kjell Ahlstedt)
* generate_extra_defs.cc:
  - Write signal flags to .defs files.
  - Write default values of properties to .defs files.
  - Write default values of properties to generated documentation.
  (Kjell Ahlstedt) Bug #785895 (Daniel Boles)
* Warn for unmatched deprecations in signals and properties.
  (Kjell Ahlstedt)

Documentation:
* Glib::ObjectBase: Don't mention GtkObject in comments.
  (Kjell Ahlstedt)
* Glib::Variant: Hide namespace Glib::detail from Doxygen
  (Kjell Ahlstedt) Bug #787698 (Daniel Boles)
* Glib::Variant: Slightly elaborate Variant<Variant> docs.
  (Daniel Boles) Bug #778219 (Daniel Boles)