Hey, Code::Blocks threw a warning on this and 511:
GitHub\Cataclysm-DDA\src\veh_interact.cpp|511|warning: comparison is always false due to limited range of data type [-Wtype-limits]|

Doesn't *break* anything, the code runs fine.  Since Jenkins parses "warning" as "ERROR" and fails the build, though, needs fixed.  Sorry.