[gtkada] Addition of Gdk_New_From_Data into Gdk.Pixbuf

[Arnaud Charlet]

> As Gdk_New_From_Data is currently missing from Gdk.Pixbuf, I created a 
> binding for it (in a child package of Gtk.Pixbuf).
> Would you consider adding this directly into to Gtk.Pixbuf?
> Is the attached code sufficient or would you prefer a diff?

A patch (diff) against svn trunk as well as a ChangeLog would be better.

The patch will probably need to be reworked before integration, since
the API you provide is pretty low-level (in particular the handling of
Destroy_Fn/Destroy_Fn_Data).

I'd suggest either remove the two last parameters, or perhaps provide a single
extra parameter: Destroy_Fn, removing the use of user data from the spec
(and still use it under the hood in the body).

The spec (comments) should probably also reflect/explain this business
of destroy/user data.

Arno