overlapping color bars in trough of progress bar

[Grace Yeung <yeung mrcmry com>]

I would like to place three overlapping color bars with difference
lengths in the trough of a progress bar.  Is it possible for me to get
the source code to gtk_progress_set_percentage and have my own version
where I can place the percentage bar one after another without removing
the previous one to achieve this?  Is there another way around it?  And
is it possible at all to have the three different colors since there's
only one place to set the color i.e. style->bg?  Thanks!

Grace