pidgin/pidgin

Convert the gplugin subproject to use the auto fallback stuff of dependency.

Testing Done:
Verified the the purples gir's loaded and were able to call into gplugin under python, when built as a subproject and against a system installed version.

Reviewed at https://reviews.imfreedom.org/r/937/
<?xml version="1.0" encoding="UTF-8"?>
<gresources>
<gresource prefix="/im/pidgin/Pidgin3/">
<file>logo.png</file>
<file compressed="true">About/about.ui</file>
<file compressed="true">About/about.md</file>
<file compressed="true">About/credits.json</file>
<file compressed="true">Accounts/actionsmenu.ui</file>
<file compressed="true">Accounts/chooser.ui</file>
<file compressed="true">Accounts/entry.css</file>
<file compressed="true">Accounts/menu.ui</file>
<file compressed="true">Avatar/avatar.ui</file>
<file compressed="true">Avatar/menu.ui</file>
<file compressed="true">BuddyList/window.ui</file>
<file compressed="true">Conversations/infopane.ui</file>
<file compressed="true">Conversations/invite_dialog.ui</file>
<file compressed="true">Conversations/menu.ui</file>
<file compressed="true">Conversations/tab-label.css</file>
<file compressed="true">Conversations/window.ui</file>
<file compressed="true">Debug/debug.ui</file>
<file compressed="true">Debug/filter.css</file>
<file compressed="true">Debug/plugininfo.ui</file>
<file compressed="true">Log/log-viewer.ui</file>
<file compressed="true">Plugins/dialog.ui</file>
<file compressed="true">Plugins/menu.ui</file>
<file compressed="true">Prefs/credentials.ui</file>
<file compressed="true">Prefs/credentialprovider.ui</file>
<file compressed="true">Prefs/ip.css</file>
<file compressed="true">Prefs/prefs.ui</file>
<file compressed="true">Prefs/vv.ui</file>
<file compressed="true">Privacy/dialog.ui</file>
<file compressed="true">Protocols/chooser.ui</file>
<file compressed="true">Roomlist/roomlist.ui</file>
<file compressed="true">Whiteboard/whiteboard.ui</file>
<file compressed="true">Xfer/xfer.ui</file>
<file compressed="true">closebutton.ui</file>
<file>icons/16x16/status/pidgin-user-available.png</file>
<file>icons/16x16/status/pidgin-user-away.png</file>
<file>icons/16x16/status/pidgin-user-busy.png</file>
<file>icons/16x16/status/pidgin-user-extended-away.png</file>
<file>icons/16x16/status/pidgin-user-invisible.png</file>
<file>icons/16x16/status/pidgin-user-offline.png</file>
<file>icons/16x16/status/pidgin-user-unavailable.png</file>
</gresource>
</gresources>