Sorry for the long subject line, tried to make it googleable.
Stumbled on a very weird bug: A satellite tracking lib used in my OOT gave NaNs when using QT, but not with WX or NoGUI.
After a long long confusion and getting glibc debugging working (Yeah, I'm green) I realized
that QT is using my local (estonian), and thus strtod(buff, NULL) which was used to parse the TLE string, used "," as the decimal separator.
Decided to leave this on the list in case anyone else stumbles on this.