I am preparing a patch for testing that uses the icons from the current
theme and as a fallback (windows and mac) the tango icons. Since there
exists a naming convention for icon files we can easily switch to
another icon set.
The patch is ready for test and can be found at
https://savannah.gnu.org/patch/index.php?8614
Under windows, the location of the necessary qt-dlls for svg-icons is
important. They are currently located in subdirectories of "plugins" in
the installation directory. The icons are only visible in windows when
"plugin" is located in the "bin" directory.