Patches for setting up the UTF8-named directory for BOOST

[tjcw]

Proposed changes

I have troubles unpacking BOOST on AIX, because AIX does not support unicode file/directory names and there is a file in BOOST tests with a unicode name. This PR combines with a PR in the BOOST 'wave' repository so that the directory is unpacked with a regular name and renamed to its unicode name at bootstrap time. boostorg/wave#233 is the PR to look at.

Types of changes

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• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Code style update (formatting, renaming)
• Refactoring (no functional changes, no api changes)
• Documentation content changes
• Other (please describe):
  Usability improvement for BOOST on AIX

Checklist

Put an x in the boxes that apply. You can also fill these out after creating the PR. If you're unsure about any of them, don't hesitate to ask. We're here to help! This is simply a reminder of what we are going to look for before merging your code.

• I searched the discussions
• I searched the closed and open issues
• I read the contribution guidelines
• I added myself to the copyright attributions for significant changes
• I checked that tests pass locally with my changes
  I checked that the 'wave' tests still pass on my Linux workstation after making the change.
• I added tests that prove my fix is effective or that my feature works
• I added necessary documentation (if appropriate)

Further comments

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