Quick fix, maybe the .deb needs to configured with
$cmake -DUSE_GPSD=off ../
This will build a configuration that does not use the libgps, even if present.
Longer term, as I suspected, we need to do some version checking of libgps in the cmake script.
That's all very well for source builders, but...
Sadly, this will need a run-time check as part of the .deb install process to validate the library version.
Or, most probably, I will need to do dynamic library loading at run-time in the code if a usable version of libgps is found...