Let Xcode install Git on macOS (alternative to #485)

[katrinleinweber]

As suggested in #485. Only one of either that PR or this one should be merged, not both ;-)

Because this Xcode-based install is signed, there are no security prompts we have to ask learners to bypass. Also, Apple will provide learners with Git updates automatically.

Edit: Screenshot for completeness, posterity & illustration.

[fmichonneau]

@iglpdc, @nhejazi, @daisieh, @kekoziar, @munkm, does this look ok to you?

It seems like a good solution but I don't know enough about macOS to know of potential downsides.

[katrinleinweber]

Would a recording of the process help decide this? https://www.youtube.com/watch?v=SPypSKO27AY pretty much shows the process, except that the software update dialog appears with the xcode-select --install command rather than with git --version or similar.

[daisieh]

I think that these instructions seem really clear and make sense to me! I haven't tried them myself (not ready to upgrade to Mojave), but they jibe with my memories of installing Git in the past.

[nhejazi]

This seems good to me. I can't easily access a macOS machine currently but from past (daily) use of one over the last few years, I recall xcode-select --install being necessary for a variety of reasons when doing any kind of scientific computing and/or software development --- so, it seems fine to add Git to that list as well.

[fmichonneau]

thanks all!

[katrinleinweber]

Cool, thanks :-)