Cleanup build scripts

[justsmth]

Description of changes:

• Realign logic between the aws-lc-sys and aws-lc-fip-sys build scripts.
• Log the version of Clang being used for bindgen.
• Utilize macro to ensure consistent conditional compilation condition.

Callout

• Bindgen 0.69.5 should now support Clang 19.1

Testing:

Added test to verify that builds succeed w/ Cland 19.1 and bindgen.

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 ✅

Project coverage is 92.62%. Comparing base (c358484) to head (099f3ac).
Report is 99 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #561      +/-   ##
==========================================
- 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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