Jython's sys.executable is a shell script on POSIX (and .bat on Windows) and 
thus can't be used as a shebang line interpreter.

The following patch works around this by calling sys.executable via /usr/bin/env 
in shebang lines on platforms where sys.platform.startswith('java') and 
sys.executable's MAGIC is '#!'.

Jython on Windows is a separate issue -- Jython probably has to ship a .exe to 
solve the problem there. This fix doesn't apply to Windows because 
sys.executable's MAGIC is not '#!' there.

Marking as a higher priority because installed scripts on Jython aren't 
executable without this fix

Original distutils-sig discussion: http://www.nabble.com/Shebang-lines-on-
Jython-td16730414.html