scripts/make.py: discover Cython sources for "clean" instead of hardcoding them

[ThomasWaldmann]

The hardcoded cython_sources list in scripts/make.py had drifted from reality: it listed 13 of the 21 .pyx modules. Missing were chunkers/base, chunkers/fastcdc, chunkers/goldilocks_aes, chunkers/phte_chunker, chunkers/rabin_aes, chunkers/toeplitz_aes, legacy/crypto/low_level and platform/netbsd.

Consequence: python scripts/make.py clean silently left those modules' generated .c files and compiled extension modules behind. That is how stale *.cpython-3XX.so files from an older Python version end up lingering in a working tree, and it means the documented rebuild recipe (make.py clean && pip install -e .) does not actually give a clean rebuild for those modules.

Found while setting borg up on a fresh FreeBSD box: after switching that checkout from Python 3.12 to 3.14, clean left six cpython-312 chunker extensions behind.

Fix

Discover the sources with glob("src/borg/**/*.pyx") instead of maintaining a second hand-written list next to the one in setup.py. New modules are then covered automatically and the list cannot go stale again.

Verification

• The glob reproduces setup.py's cython_sources list exactly - same 21 paths.
• End-to-end on FreeBSD 15.1 / Python 3.14: before clean, 17 compiled .so and 21 generated .c; after clean, 0 and 0, with git status showing no leftover build artifacts. Previously the same command left 8 modules' artifacts untouched.
• Rebuilt from the cleaned tree and ran the full test suite: 2639 passed, 975 skipped.
• ruff check / ruff format --check clean.

🤖 Generated with Claude Code

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 86.94%. Comparing base (69acada) to head (6cef09f).
⚠️ Report is 33 commits behind head on master.
✅ All tests successful. No failed tests found.

Additional details and impacted files

@@            Coverage Diff             @@
##           master   #10156      +/-   ##
==========================================
+ Coverage   86.88%   86.94%   +0.06%     
==========================================
  Files         101      101              
  Lines       17857    17983     +126     
  Branches     2709     2737      +28     
==========================================
+ Hits        15515    15636     +121     
- Misses       1636     1639       +3     
- Partials      706      708       +2     

☔ View full report in Codecov by Harness.
📢 Have feedback on the report? Share it here.