desktop hook for theme changes

[Stefan Kost <ensonic hora-obscura de>]

hi,

people (including me) where wondering about the duplicated png files in each
gtk-doc manual. I believe this was historically done to avoid the gtk-doc
dependency for users (which I don't think is a problem nowadays - the package is
small).
Anyway I was wondering, if those 4 black icons could instead be symlinks to the
theme icons. This would safe a bit of space and would align the look more with
the theme. One could even patch the colors in the css.

The only think needed would be a hook to update those symlinks when the theme
changes. Do we have anything like this in the platform?

Stefan