I'm going to take a guess that the "swig" package is not installed on your system so when you ran the "cmake ../" step prior to building op25 it generated makefiles without swig support.  It'll still compile and install quite happily but won't run...  (ask me how I know!)

To fix the problem you need to do a "sudo apt install swig" or whatever is equivalent on OSX, then delete and re-create the op25/build directory followed by the remaining build/install steps.