Made date time sources usage more explicit in setup.py

[WillAyd]

Not sure this fully solves #30236 but doesn't hurt and makes things more explicit

[pep8speaks]

Hello @WillAyd! Thanks for updating this PR. We checked the lines you've touched for PEP 8 issues, and found:

There are currently no PEP 8 issues detected in this Pull Request. Cheers! 🍻

Comment last updated at 2019-12-13 22:11:36 UTC

[jreback]

hmm i am always leary of changing things like this, last time we did things didn't recompile properly locally. meaning if you then just change something that was formerly a source (but now only a depends) it didn't recompile unless you clean.

@jbrockmendel can you test out.

[jbrockmendel]

I agree with both @WillAyd that this looks correct and is more explicit and @jreback that in the past this has been a fragile minefield. On the margin I'm inclined to trust Will on this as it is easy to revert if problems pop up.

[WillAyd]

Cool thanks both for the feedback. Just to clarify on this one I'm just removing sources that aren't used by the module at all, not necessarily converting from sources -> depends

The problem I'm trying to address is that with parallel builds everything in sources gets recompiled when specified as such, and I think race conditions could make things fail

This doesn't fully solve the recompilation problem but just removes the compilation step from modules that don't reference those C extensions at all, whether directly or through import of another module

[WillAyd]

Any objection to rolling with this for now and reverting if issues pop up? Have it as a mini goal to get parallelized builds which I think this is a pre-cursor of

[jbrockmendel]

+1

[WillAyd]

Cool I'll merge for now and obviously can revert if anything pops up

cc @pandas-dev/pandas-core for visibility