[Distutils] build_scripts and #!/usr/bin/env

[Andrew Kuchling]

The build_scripts command changes the #! line of Python scripts to
match the Python installation being used to run the setup.py script.
Currently it only fixes lines of the form #!/a/b/c/python, but leaves
'#!/usr/bin/env python' alone.  It used to also change #!/usr/bin/env
lines, but I changed that behaviour because I think it's wrong and
leaves you with no way at all to install a script that uses
/usr/bin/env .

A bug caused by this is at
http://sourceforge.net/tracker/index.php?func=detail&aid=409430&group_id=5470&atid=105470
I think this is a silly use case, where you want pydoc to use a
different Python from the default interpreter you get by running
'python', but will bow to the SIG's opinion.

So, fix /usr/bin/env lines or not?

--amk