2004-08-30  Michael Natterer  <mitch@gimp.org>

	* app/plug-in/plug-in-progress.[ch]: added boolean return values
	to plug_in_progress_install(), uninstall() and cancel(). Added
	checks to make sure the installed progress_callback exists, has
	the correct signature and was installed by this plug-in.

	* tools/pdbgen/pdb/progress.pdb: use the return values to let the
	PDB wrappers succeed/fail.

	* app/pdb/progress_cmds.c: regenerated.