Use PyOS_setsig in macos backend

[QuLogic]

PR summary

While looking at #27953, we compared 3.7 with 3.8, and noticed the former used PyOS_setsig while 3.8+ uses sigaction.
The docs for this function say it wraps sigaction or signal, and not to use those functions directly.

I believe @ksunden did test this out while trying to see if it would fix anything, and didn't see any change.

PR checklist

• [n/a] "closes #0000" is in the body of the PR description to link the related issue
• new and changed code is tested
• [n/a] Plotting related features are demonstrated in an example
• [n/a] New Features and API Changes are noted with a directive and release note
• [n/a] Documentation complies with general and docstring guidelines

[greglucas]

Thanks for cleaning this up! Works as expected testing with ctrl+c locally.

[ksunden]

Indeed I did try this and it worked

[ksunden]

test failures are likely unrelated, but would like the macos ones to pass on this PR, so reran those. Anyone can merge on green macos CI (I'm ignoring Appveyor, which has been failing on environment creation recently, and does not matter for a mac specific PR)