Mitigate bindgen 0.69 w/ clang 19.1 incompatibility

[justsmth]

Issues:

Addresses #476

Description of changes:

• For both aws-lc-sys and aws-lc-fips-sys: Detect whether clang 19.1 (or later) is being used, and avoid using bindgen 0.69.x if so.
• Update aws-lc-fips-sys so its logic more closely aligns with aws-lc-sys.

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license and the ISC license.

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 92.62%. Comparing base (c358484) to head (45fcdd2). Report is 96 commits behind head on main.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #559 +/- ## ========================================== - Coverage 95.80% 92.62% -3.18% ========================================== Files 61 67 +6 Lines 8143 9366 +1223 Branches 0 9366 +9366 ========================================== + Hits 7801 8675 +874 - Misses 342 420 +78 - Partials 0 271 +271 ```

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