Currently passing -DINPUT_trace=YES to CMake results in a build configured without trace even if all prerequisites are installed. Specifying -DINPUT_trace=yes works when all prerequisites are installed, but silently reverts to build without trace support when any prerequisites are missing.

It would be good to accept any boolean values as input if possible, or at least the input to be not sensitive to case. It would also be good to display an error message when trace is requested but dependencies are missing.