Maybe I was to tired when I tried to fix it, but my solution didn't work. Then I let the quartz run free and measured the offset against the PPS pulse. It also gave a straight line.
Feedback is welcome.
Gurus for the non-i386 architecture can preview the stuff, but maybe not yet implement similar routines as long as the interfaces haven't settled down. Especially we have every time routine doubled now, once for microseconds, once for nanoseconds. I'd also like to minimize the architecture-specific time.c.