Related to: https://bugs.python.org/issue32429 

The bahavior of Modules/Setup{,.dist,.local} looks inherited from an old time:

- A Setup.dist exist
- ./configure copies it to Setup (cp $srcdir/Modules/Setup.dist Modules/Setup)
- ./configure installs a dummy Modules/Setup.local file
- One can add an optional things to Setup.local
- One can have to modify Setup itself (to modify things)

From this point in time, Setup is newer than Setup.dist (as copied from it), the following can happen:

- The Setup file is manually modified, it's still newer than Setup.dist, it does not change the situation
- The Setup.dist file gets updated (via a git checkout or git merge), the Makefile detects it and warn the user:
  - Either the user modified the Setup file and don't want it to be overridden
  - Either the user didn't modified it and just want the updated version

We don't know, so the Makefile is printing a warning telling he don't know and we have to fix the situation. First problem is: this warning is invisible due to the high load of Makefile prints, this is the issue https://bugs.python.org/issue32429.

Proposed solutions are:

- Xavier de Gaye: Use Setup.dist instead of Setup when Setup is missing (https://bugs.python.org/issue32429#msg309078)
- Just keep a single versionned Setup file, let those who modify it use branches to commit their modifications

Marc-Andre Lemburg noted that for those using a sources tarballs, in the single Setup file case, it's not nice for them to loose the original content of Setup when modifying it, and being able to do a `cp Modules/Setup.dist Modules/Setup` to restore it is nice.

Personally I'll go for a single Setup file (No .dist, no .local, no copy), that one can modify and commit, delegating the pain of merging to git, as I prefer simple solutions.

I don't think the importance of keeping a ".dist" backup is worth the pain and we're not doing it for other files (If one using a source tarball is modifying a .c file, the original content is lost too, and we'll not provide .c.dist files).