Having the version macro in the config.h and consequently in the main
vehicle header means that whenever the version changes we need to
compiler the whole vehicle again. This would not be so bad if we weren't
also appending the git hash in the version. In this case, whenever we
commit to the repository we would need to recompile everything.
Move to a separate header that is include only by its users. Then
instead of compiling everything we will compile just a few files.