pidgin/pidgin

Make our windows builds usable from meson.
release-2.x.y
2021-04-19, Gary Kramlich
2ff89178eb3d
Make our windows builds usable from meson.

This creates our pkg-config files on windows as well as fixes an include in
pidgin.h which can cause some issues.

This isn't usable as is, as you need a machine-file and a pkg-config wrapper
to make this all work, but that will be updated in the win32-dev.7z file thats
on data.imfreedom.org.

Testing Done:
Compiled guifications2 (which now uses meson) on windows and verified it works.

Reviewed at https://reviews.imfreedom.org/r/615/
/** @page plugin-signals Plugin Signals
@signals
@signal plugin-load
@signal plugin-unload
@endsignals
@see plugin.h
<hr>
@signaldef plugin-load
@signalproto
void (*plugin_load)(PurplePlugin *plugin);
@endsignalproto
@signaldesc
Emitted when a plugin is loaded.
@param plugin The plugin that was loaded.
@endsignaldef
@signaldef plugin-unload
@signalproto
void (*plugin_unload)(PurplePlugin *plugin);
@endsignalproto
@signaldesc
Emitted when a plugin is unloaded.
@param plugin The plugin that was unloaded.
@endsignaldef
*/
// vim: syntax=c.doxygen tw=75 et