(Not sure if this is the right section, but the "bugs" section has no "Report new bug" button?)
FreeBSD is switching from libstdc++ (GNU) to libc++ (LLVM) and one of the consequences is that the isinf() and isnan() macros are more strict on their input arguments: integer variables (like car->ctrl->gear) are not accepted.
For car->ctrl->gear, the tests can simply be removed because integers cannot represent infinity nor NaN.
See also http://svnweb.freebsd.org/ports?view=revision&revision=327336
Under "tickets" there is as well a "bug" button, but do not worry:-) I will take a note and include this into 1.3.5 if it does not cause problems (your argument is very reasonable, so I guess it will just work).
Thank you very much for the report:-)
Best regards
Bernhard
Applied in CVS