Here's the diff corresponding to it.

I just realized I've been building binaries with the debug screen I never finished. Not relevant, but, oops.

Actually I think I just found the problem.Try this.

Okay, yeah, that worked! It's loading routes now!

Enqiring minds want to know: What was it?

Made it open the directory you specified, but not actually open the route files in it. And I kept not seeing it because:
1) I was grepping strace output for the wrong thing
2) I did clean up the old routedir on my empeg, and then kept testing it (with gpsapp_host) on my laptop, where the old directory was still there (as was the new directory) with the same files.

Duh. This is what happens when you do things on several machines at once and aren't concentrating on any of them.

Well, the important thing is it all works now.

THANK YOU ALL!!!!

Well, at least the thing I was debugging on another machine wasn't a fluke also, but sadly that means I still am actively having the problem I'm trying to kill.

It's way too hard trying to simulate something going into I/O wait.