First of all, I managed to figure out that even when linking /etc/localtime to the right timezone file, mktime and friends are not able to give me the right local time from UTC time (it seems to be off by about 2x the timezone offset).

The glibc on mine at the time (which was 2.0b11, I think) was doing something weird, like opening files in the wrong place or something.

I wish I remembered what I eventually discovered, but my laptop is at home and just fell over (thank you Dell for the crappy power cable) so even if I have notes, I can't look now.

As to NMEA over IRDA, I think Kim Salo was doing something like that at the beginning of his project, actually.