Spaces in Python path make pip-installed launchers fail on Windows

Launchers (console_scripts) installed via pip under Windows fail when Python is installed in a path that contains spaces (e.g. C:\Program Files (x86)\..., which will be the default directory for 3.5):

$ pip install vanity
$ vanity
Failed to create process.

It does work, when the package is installed manually via python setup.py install. Also, both ways install the same <packagename>.exe launcher (so this is different from #1997 and #1999).

Via pip install, the shebang in <packagename>-script.py is #!C:\Program Files (x86)\Python27\python.exe instead of (via python setup.py install) #!"C:\Program Files (x86)\Python27\python.exe"

Note that both launcher scripts actually work when executed directly: only the launcher .exe seems to be more strict about quoting. So it may be good to (also) make the launcher more forgiving (is the bug tracker for distlib non-public?).

[fkrull]

FYI: The fix for the underlying setuptools issue (https://github.com/pypa/setuptools/issues/398) is now merged there.

[z3ntu]

BUMP!