build: Use apple-clang 21; remove SourceLocation stub

[mathbunnyru]

No description provided.

[codecov]

Codecov Report

❌ Patch coverage is 83.33333% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 82.61%. Comparing base (c2b129b) to head (2f75d4f).

Files with missing lines	Patch %	Lines
src/util/log/Logger.cpp	83.33%	2 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #3123      +/-   ##
===========================================
- Coverage    82.64%   82.61%   -0.04%     
===========================================
  Files          397      397              
  Lines        16034    16034              
  Branches      8399     8399              
===========================================
- Hits         13252    13247       -5     
- Misses        1660     1667       +7     
+ Partials      1122     1120       -2     

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[godexsoft]

Yay. hopefully it really does work on all platforms now