doc: suggest xcode-select --install

[gibfahn]

If you don't have the full Xcode installed, the command-line tools are
all you need.

Fixes: #6449
Refs: #9215

cc/ @nodejs/platform-macos

Checklist

• documentation is changed or added
• commit message follows commit guidelines

Affected core subsystem(s)

doc, build

[gibfahn]

@mscdex cf: #9215 (comment)

How far back does xcode-select --install work for older versions of Xcode? I don't really mind either way, I just thought it might be useful to keep instructions for new and old if the instructions will differ.

It looks like it works from 10.9 (mavericks), so I think we should be fine. IMHO it's unnecessary to go into any more detail, or to consider the full Xcode install for Xcode 7.x, we can always reconsider if someone has an issue.

[lpinca]

Can we reword this a bit? At the moment it says "On macOS, you will also need -> Xcode -> You also need to install the Xcode Command Line Tools ...".

A full installation of Xcode is not required, so maybe this can be changed to

On macOS, you will also need:

• The Xcode Command Line Tools ...

[gibfahn]

Updated, PTAL.

[Trott]

This seems confusing. Should I run the command line or should I open the GUI and "find them"? (I imagine the answer is "either will work" but I'm not sure that's clear from this text. If xcode-select --install will work everywhere all the time, then maybe let's just leave it at that? Or preface the GUI content with "Alternatively, " so that people know it's one or the other?

[Trott]

Can someone who doesn't have the full XCode installed confirm that this actually works (that is, they can compile node this way)?

[lpinca]

@Trott can confirm I've always used this way.

[gibfahn]

Or preface the GUI content with "Alternatively, " so that people know it's one or the other?

@Trott I went with this. Technically you can install both and switch between them with xcode-select --switch /path, but that's TMI.

LGTY?

[Trott]

Nit: comma after Alternatively

[Trott]

Nit: comma after installed

[Trott]

LGTY?

Text looks good to me. (Left a couple of punctuation nits, but whatever.) I don't know enough about the actual correctness of the content to provide a review/approval. I don't doubt that it's correct, but I'm not knowledgable enough to put a stamp on it. If you and @lpinca both say it's correct, that's good enough for me.