gtkmarshal.h?

[Owen Taylor <otaylor redhat com>]

Currently we:
 
 - Export the gtk_marshal_* symbols
 - Install gtkmarshal.h
 - Include gtkmarshal.h from gtksignal.h

If we continue to do this, then we'll need a policy of never removing
any marshallers from gtkmarshal.list which is not so nice, since
the set of marshallers is really an internal implementation detail.

However, since we also did this for GTK+-1.2, we can't simply
unexport them without causing backwards-incompatibilities (though we
may well have already caused such, since we haven't really worried
about this before.)

Quick and dirty solution - slap a:

  #if !defined(GTK_DISABLE_DEPRECATED) || defined(BUILDING_GTK)

Around gtkmarshal.h. Harder solution, have two lists of marshallers:

 - Exported marshallers - those we exported in GTK+-1.2.

 - Unexported marshallers.

And generate one set in the public header as gtk_marshal_* and 
put GTK_DISABLE_DEPRECATED around. And generate the
second set in a private header as _gtk_marshal_*.

Thoughts? It isn't awful if we don't do anything here, but I'd
like to at least deprecate use of the builtin GTK+ marshallers.

                                        Owen