Re-add Setup.local for Darwin (incl _ssl)

The change to add darwin/arm64 support accidentally dropped the Setup.local
configuration for Darwin, losing a few modules. Add them back in.

Test: on Mac, ./py3-cmd -c "import ssl"
Bug: 257239885
Change-Id: Id1ef437d82387f2b29e5f2e84374afbaabee3584
3 files changed