Here's a new patch that doesn't apply the workaround when there's arguments 
(whether those arguments were in the script, or due to the fact that there's non 
ascii chars involved, requiring -x) and emits a warning message about it to 
stderr

With some tests

The warning ends up looking like:

$ jython setup.py develop
running develop
running egg_info
writing dependency_links to scripted.egg-info/dependency_links.txt
writing scripted.egg-info/PKG-INFO
writing top-level names to scripted.egg-info/top_level.txt
writing entry points to scripted.egg-info/entry_points.txt
reading manifest file 'scripted.egg-info/SOURCES.txt'
writing manifest file 'scripted.egg-info/SOURCES.txt'
running build_ext
Creating /Users/pjenvey/src/java/jython-trunk-clean3/jython-trunk-
clean3/Lib/site-packages/scripted.egg-link (link to .)
scripted 0.0dev is already the active version in easy-install.pth
WARNING: Unable to adapt shebang line for Jython, the following script is NOT 
executable
         see http://bugs.jython.org/issue1112 for more information.
Installing scripted.py script to /Users/pjenvey/src/java/jython-trunk-
clean3/jython-trunk-clean3/bin

Installed /Users/pjenvey/src/python/scripted
Processing dependencies for scripted==0.0dev
Finished processing dependencies for scripted==0.0dev