OpenUSD Build without Boost when using OpenVDB 12 or newer

Description of Change(s)

In OpenVDB 12 there is no more header dependency on Boost (and it can optionally be built entirely without Boost). Therefore OpenUSD itself does not need a direct dependency on Boost when using this version.

This adds OpenVDB version detection based on the header files, and moves CMake OpenVDB finding before Boost so that the version can be checked.

Checklist

[x] I have created this PR based on the dev branch
[x] I have followed the coding conventions
[ ] I have added unit tests that exercise this functionality (Reference: testing guidelines)
[x] I have verified that all unit tests pass with the proposed changes
[x] I have submitted a signed Contributor License Agreement (Reference: Contributor License Agreement instructions)

Jan 26 '25 23:01 brechtvl

Thanks , Brecht. This is super useful.

I'll also soon be putting up a PR to upgrade to VDB 12.0.1 (or 12.1? Not sure what it'll be) which will include the clang fixes as well. So this is fortuitous timing.

Jan 27 '25 14:01 dgovil

Filed as internal issue #USD-10595

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Jan 27 '25 17:01 jesschimein

/AzurePipelines run

Jan 27 '25 17:01 jesschimein

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Jan 27 '25 17:01 azure-pipelines[bot]

/AzurePipelines run

Mar 31 '25 16:03 jesschimein