Thanks to everyone who has helped me out in these first few hours. Command-line arguments go in the text field, and you can choose between two methods of writing the log file. A lot of this stuff can be GUI-fied, perhaps. Check out the popular Windows utility Q3ME for a taste of what may be possible down the road. If you're getting lots of compile errors, as I am, the list of error messages at Q3ME's site is very useful.
Nobody seems able to get it to work though.
The picture on the left is the original compile of this map, done in VPC with the Windows tools. The picture on the right is of the Q3Map on MacOS compile. I didn't run -light on this, so ignore the fullbrightness. Notice how the textures are improperly scaled, and how some are missing. This is PfhorSlayer's The Crypts , btw.