At a guess, the version of `make` used in your environment was not able to handle a comment.  However, Python 2.7 has now reached end-of-life and as such I'm closing this issue.  If you can still reproduce the issue with a modern version of Python (3.6-3.8) we can consider reopening the issue, but as UnixWare is not a supported platform the chances of anyone else being able to track down the issue and supply a patch are pretty slim.