GTK+ modules loading changes

[Bastien Nocera <hadess hadess net>]

Heya,

This will affect you if you install a GTK+ module.

The latest version of gnome-settings-daemon[1] will load GTK+ modules
using .desktop files in the
$(libdir)/gnome-settings-daemon-3.0/gtk-modules/ directory.

The desktop files are fairly simple:
[GTK Module]
Name=My module
Description=My super GTK module
X-GTK-Module-Name=supermodule

This will make the libsupermodule.so GTK+ module be loaded by GTK+.

If you need the module to be conditionally loaded, you'd add those 2
lines to your .desktop file:
X-GTK-Module-Enabled-Schema=org.gnome.desktop.interface
X-GTK-Module-Enabled-Key=accessibility

With your own schema and key there, as you would expect. Note that the
schema and key *must* be defined by gnome-settings-daemon or one of its
dependencies (such as gsettings-desktop-schemas), or shipped with your
module.

Finally, if you require 2 modules to be loaded in a certain order,
you'll need to define the X-GTK-Module-Name as "module1:module2". This
is the case for the a11y modules.

I already added patches for at-spi[2], at-spi2-atk[3], and filed a bug
for gnome-packagekit[4]. If somebody wants to do that for libcanberra,
go for it.

Cheers

[1]: https://bugzilla.gnome.org/show_bug.cgi?id=633191
[2]: https://bugzilla.gnome.org/show_bug.cgi?id=633192
[3]: https://bugzilla.gnome.org/show_bug.cgi?id=633194
[4]: https://bugzilla.gnome.org/show_bug.cgi?id=633195