CI: use GCC 14 in Linux build

[cjmayo]

Ubuntu 24.04 packages GCC 13. GitHub add GCC 14 to their runner.

---

There are now some CMake issues to sort out with the Clipper2 snapshot!

CMake Error: install(EXPORT "manifoldTargets" ...) includes target "cross_section" which requires target "Clipper2" that is not in this export set, but in multiple other export sets: lib/cmake/clipper2/Clipper2Targets.cmake, share/clipper2/clipper2Targets.cmake.
An exported target cannot depend upon another target which is exported multiple times. Consider consolidating the exports of the "Clipper2" target to a single export.
-- Generating done
CMake Generate step failed.  Build files cannot be regenerated correctly.

[elalish]

Interesting, I guess file an issue on Clipper2? Or is this a problem in our own CMake?

[cjmayo]

I've built locally with that Clipper2 snapshot, but installing into my system first before building Manifold. So I wasn't expecting this - but haven't had time to look yet either.

[pca006132]

Interesting, I think the clipper2 update is separate from the GCC update. I forgot a lot of cmake trickeries now, need to check if the best solution is to fix things here or ask upstream to have a single export.

[cjmayo]

I've dropped the clipper2 update commit in favour of #817.

[cjmayo]

Compiling on GCC 14 after #817 merged but lcov fails linux-test-project/lcov#296

Processing ./test/CMakeFiles/manifold_test.dir/smooth_test.cpp.gcno
geninfo: ERROR: mismatched end line for _ZN23Smooth_Tetrahedron_Test8TestBodyEv at /home/runner/work/manifold/manifold/test/smooth_test.cpp:26: 26 -> 39
	(use "geninfo --ignore-errors mismatch ..." to bypass this error)

[pca006132]

I think it is fine to disable lcov for GCC 14 for now?

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 89.21%. Comparing base (d437097) to head (914743a).
Report is 29 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #816      +/-   ##
==========================================
- Coverage   91.84%   89.21%   -2.63%     
==========================================
  Files          37       61      +24     
  Lines        4976     8467    +3491     
  Branches        0      930     +930     
==========================================
+ Hits         4570     7554    +2984     
- Misses        406      913     +507     

☔ View full report in Codecov by Sentry.
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[cjmayo]

Looking more closely it was actually GCC 13 that was failing (GCC 14 job hadn't got that far).

It passes if --ignore-errors mismatch is used with lcov .

Then needed --gcov-tool gcov-${{ matrix.gcc }} for GCC 14.

[elalish]

Thanks!