[Vala] Package files for bindings.

["Alberto Ruiz" <aruiz gnome org>]

Hi there,

I'm now maintaining the clutter vala bindings on an external repository and I'm not sure on what should I do regarding the vapi directory.

I think that we should ship a .pc file with each external binding (not vala specific). The reason is to be able to have several vapidirs (with the .vala/.deps file) for each binding. That would allow isolation and forward compatibility. For example, we already have had problems moving Math to 
GLib.Math, the math.vala file is not removed whenever you install newer versions and you may fall into incompatibility problems (source code that compiles in one box but not in others even with the same vala version).

This could be achieved using a new variable (I'll call it vapidir in an originality explosion), and asking valac to check that variable and add it to the vapidirs list. 

What do you think?
-- 
Un saludo,
Alberto Ruiz