The PEP 3101 float formatting code (in Objects/stringlib/formatter.h)
uses PyOS_ascii_formatd for all specifier codes except 'n'.  So applying
the patch would fix the issue that was originally brought up in msg58485.

I think the approach of the patch (if not its content, I haven't
inspected it yet) is correct.  Fix the underlying code and benefit from
this everywhere.  I don't think we should change the tests to be more
tolerant, I think we should be consistent across platforms.

My only concern is breaking code in the wild.  This seems like a change
with wide-reaching implications.

I think 'n' should also be addressed.  It calls PyOS_snprintf directly.

I'll review the patch and comment back here.  Unfortunately, I don't
have a Windows box set up for testing.