How to change GtkEntry background

[Paul Foley <mycroft actrix gen nz>]

I want to display some data in an array of Entry widgets, and I'd like
to change the text background on a per-widget basis to represent a few
bits of other data associated with each entry.  Is it possible?  I can
only get a single-pixel-width line around the border to change colour,
which is not very helpful.

The colours have to change whenever the content changes.

[What I'd _like_ to be able to do is something like

  gtk_widget_set_named_style(my_widget, "foo")

to make the widget use a style "foo" defined in an rc file]

-- 
Quid enim est stultius quam incerta pro certis habere, falsa pro veris?
                                                                 -- Cicero
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