RFR: 8340804: doc/building.md update Xcode instructions to note that full install is required [v2]

[Julian Waters]

On Tue, 24 Sep 2024 13:06:16 GMT, George Adams <gdams at openjdk.org> wrote:

>> Since JDK17 there has been a dependency on metal in the macOS builds which is only available as part of the full Xcode IDE (rather than command-line tools). We currently recommend only installing the command-line tools in the building.md doc which is incorrect.
>> 
>> See https://github.com/openjdk/jdk/blob/e1c4d3039f6b5106ce3f65d50f607eacc2a8d168/make/autoconf/toolchain.m4#L681
>
> George Adams has updated the pull request incrementally with one additional commit since the last revision:
> 
>   run pandoc

Marked as reviewed by jwaters (Committer).

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PR Review: https://git.openjdk.org/jdk/pull/21154#pullrequestreview-2325195639