Good morning, another snowy day here in the UK, so once again no chance to try things out properly...however, I can try to be helpful.

and

both have the same or similar answer.
Basically the build process is supposed to run a kde app that converts svgs to the prescaled pngs. However I have not managed to get it installed under scratchbox in my ubuntu install. There is a similar app that I believe Gerrit uses to 'fake' this step, but it just segfaults for me. Anyway...basically Gerrit has providees the icons-prescaled.gz which you can extract in the navit/xpm folder
either after installing a build that didn't have them. Or (in my case) in the source folder before building the deb in the first place.

This then means all the icons work again.

as for why the buttons don't work for you lemmy slender...erm I have no idea.

My build may not have included Gerrits unblanking fix, I can't remember if it had already been integrated. Last I checked Gerrit's fixes where still waiting to get integrated.

ernia: assuming espeak takes the same format as flite then that should be a trivial switch.
However one thing I would like to investigate at some point is switching it to use pre-canned 'human-read' audio clips rather than text to speech. I have no idea if that would be better/worse performance wise. But I much prefer the quality of speech my tom-tom gives than the flite stuff.
One idea I've had I might look into is something that actually takes the same parameters as flite, but first looks up a mapping table to see if it has a mp3 or somesuch to play for that phrase. And falls back to flite if it has none.
Maybe I'll look at this when I'm satisfied with the overall performance as a navigation device.