Fix conditional that defines ATLEAST_37.

[morganwahl]

Hi!

Compilation is failing for me on Python 3.10. It looks like there's some compatibility code for versions before 3.7 vs 3.7 and later. However, the condition to define ATLEAST_37 seems to have the opposite test of what it should.

[pganssle]

Is there a reason you need this module on Python 3.10? It's a backport of zoneinfo, which is in the standard library as of Python 3.9.

[morganwahl]

I don't need it, but I have a dependency which depends on it. It might actually be unused at runtime, but this create problems since it's an error at install time.

Yes, that dependency should update their requirements to not require it on 3.10, but if this makes the install OK on 3.10 it seems like it will save some people a headache.

[morganwahl]

Actually, digging into my dependencies a little more, I see why I'm hitting this. I'm using pip-tools to generate a requirements.txt, but I generated it using an older Python version, otherwise this wouldn't be in there.

That said, this change seems to make sense, right?

[gsemet]

Please make your lib does nothing on 3.10. It is really hard to make some generic purpose package (ex: zipapp with shiv). If zoneinfo needs to be a passthrough on 3.10, let's be it, but do not fail the build !