Gtk 3.14 breakage

Hi,

Since Gtk 3.14, the ruler doesn't look good anymore: here on Fedora 21
it look black.

I filed bug http://bugzilla.abisource.com/show_bug.cgi?id=13682

I have attached a patch (against trunk). If people could test it on
Gtk3, possibly other versions, that would be helpful.

I'll backport it to AbiWord 3.0.x if it is confirmed to be working.

Thank you kindly.

Hub