tools: get the latest config.guess/config.sub and patch to support arm64_32

It's updated independently from automake which we use to pick a recent enough version.

The fake automake path is to fool the contribs in using that one prioritarily.

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v2:

Tell autoreconf to use our config.guess/sub rather than its own in contribs and VLC. We may not need update_config when RECONF is used. But in some cases we may not need RECONF at all.