Fix generated script when entry point func name is used by the script template

[hukkin]

A fix for the issue identified at the end of this message: #239 (comment)

[pfmoore]

As noted in #239, I don’t think this is a sufficiently important issue in practice to warrant the extra complexity.

[hukkin]

Fair enough, then this can be closed.

I personally wouldn't make any bets, though, that no one ever has, or ever will, try to use re, sys or __name__ as an entry point function's name.

The first two are only 2 and 3 letters, and could well have meanings (as words, abbreviations or acronyms) that totally make sense as an entry point function. Languages other than English exist too.

The way these error when used is really bad IMO. No error when building a package. No error when installing a package. A cryptic exception, pointing to a line of code not in the wrapped tool's codebase, is only raised when a user eventually tries to run the installed code. If a user wanted to file an issue, they probably would have a hard time figuring out where to.

__name__ is very unlikely to be used as an entry point name, but if it is, the result is even worse. The script can be run, but it is a no-op that exits successfully with exit code 0.