Update p5-glib2 to 1.304.

Overview of changes in Glib 1.304 (stable)
==========================================

* Fix compilation against glib < 2.34.0.

Overview of changes in Glib 1.303 (stable)
==========================================

* Revert the change to ref counting of initial wrappers of custom subclasses,
  introduced in Glib 1.300.  It caused issues with subclasses inheriting from
  Glib::InitiallyUnowned.
* Fix a test failure with perl >= 5.19.4.
* Create a GType for GSpawnFlags and register it with the bindings.

Overview of changes in Glib 1.302 (stable)
==========================================

* Avoid misusing the macro PL_na, thus preventing issues when Glib is used in
  conjunction with certain XS modules, among them XML::Parser and
  String::Approx.
* Avoid memory corruption when registering boxed synonyms repeatedly.

Overview of changes in Glib 1.301 (stable)
==========================================

* t/options.t: skip tests in non-UTF-8 locales; fixes RT#83490

Overview of changes in Glib 1.300 (stable)
==========================================

* Stable release to coincide with the release of Perl 5.18.0

Since 1.28x (The previous stable release)
-----------------------------------------
* Ensure timely destruction of initial wrapper of custom subclasses
* Start changing module version numbers in all Perl modules in the
  distribution, not just lib/Glib.pm; (Bugzilla #690464)
* Make Glib::Object subclassing more robust.  This should in particular fix
  issues revealed by the change to hash randomization introduced in perl
  5.17.6.
* Correctly handle utf8-encoded strings in GPerlArgv.  This should fix issues
  seen with utf8-encoded strings in @ARGV with, for example, Gtk2->init.

Overview of changes in Glib 1.291 (unstable)
============================================

* Ensure timely destruction of initial wrapper of custom subclasses
* Start changing module version numbers in all Perl modules in the
  distribution, not just lib/Glib.pm; (Bugzilla #690464)

Overview of changes in Glib 1.290 (unstable)
============================================

* Make Glib::Object subclassing more robust.  This should in particular fix
  issues revealed by the change to hash randomization introduced in perl
  5.17.6.
* Correctly handle utf8-encoded strings in GPerlArgv.  This should fix issues
  seen with utf8-encoded strings in @ARGV with, for example, Gtk2->init.

Overview of changes in Glib 1.280 (stable)
==========================================

Since 1.26x (the previous stable series)
----------------------------------------
* Correctly handle the boxed type for GError.
* Ensure that custom signal marshallers are always used irregardless of
  the spelling used for the signal name.
* Make the stack handling of some marshallers more robust, in
  preparation for custom Glib::Boxed converters that call back into
  Perl code.
* Add new C API gperl_register_boxed_synonym.

Since 1.270
-----------
* Fix building with perl <= 5.14.

Overview of changes in Glib 1.270 (unstable)
============================================

* Correctly handle the boxed type for GError.
* Ensure that custom signal marshallers are always used irregardless of the
  spelling used for the signal name.
* Make the stack handling of some marshallers more robust, in
  preparation for custom Glib::Boxed converters that call back into Perl
  code.
* Add new C API gperl_register_boxed_synonym.

(obache)