RFR: 8338108: Give better error message in configure if a full XCode is missing

[Erik Joelsson]

On Fri, 9 Aug 2024 10:27:25 GMT, Magnus Ihse Bursie <ihse at openjdk.org> wrote:

> The XCode command lines tools is almost, but not quite, enough to build the JDK. We still need the metal and metallib tools. The error message given by configure should be improved to indicate if this is the problem with the user's environment.

Marked as reviewed by erikj (Reviewer).

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PR Review: https://git.openjdk.org/jdk/pull/20520#pullrequestreview-2230830988