setup: drop the hack to disable linker warning 4197 on Windows
I don't see this when building on Windows with py3.8 or py3.12, so either the
code was fixed, or (more likely) the compiler stopped warning about it some time
after VS 2008. If we do have to put this back, it would probably be better to
put a `#pragma` in a header file somewhere, and avoid `setuptools` technical
debt.
https://bz.mercurial-scm.org/619
$ hg init repo
$ cd repo
$ echo a > a
$ hg ci -Ama
adding a
$ echo b > b
$ hg branch b
marked working directory as branch b
(branches are permanent and global, did you want a bookmark?)
$ hg ci -Amb
adding b
$ hg co -C 0
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
Fast-forward:
$ hg merge b
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ hg ci -Ammerge
Bogus fast-forward should fail:
$ hg merge b
abort: merging with a working directory ancestor has no effect
[255]
Even with strange revset (issue4465)
$ hg merge ::.
abort: merging with a working directory ancestor has no effect
[255]