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### Description
<!--Please explain your changes.-->

More ComplexQZ fixes.

Extra semicolons are triggeri...

Antonio Sánchez authored Oct 20, 2025 and Charles Schlosser committed Oct 20, 2025

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### Description
<!--Please explain your changes.-->

Support AVX for i686.

There was an existing work-around for windows.  Added the more generic
architecture comparison to also apply for linux.

### Reference issue
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Fixes #2991.

Closes #2991

See merge request !2037

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Tyler Veness authored Oct 23, 2025 and Antonio Sánchez committed Oct 23, 2025

It fixes this compiler error:
```
/home/tav/git/Sleipnir/build/_deps/eigen3-src/Eigen/src/SparseCore/SparseVector.h:143:19: error: cannot convert ‘int’ to ‘const Eigen::internal::CompressedStorage<boost::decimal::decimal64_t, int>::Scalar&’ {aka ‘const boost::decimal::decimal64_t&’}
  143 |     m_data.append(0, i);
      |                   ^
      |                   |
      |                   int
```

This change matches what SparseMatrix does:
https://gitlab.com/libeigen/eigen/-/blob/master/Eigen/src/SparseCore/SparseMatrix.h#L430-L438

See merge request !2040

Antonio Sánchez authored Oct 24, 2025 and Rasmus Munk Larsen committed Oct 24, 2025

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### Description
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Eliminate use ...

Antonio Sánchez authored Oct 24, 2025 and Rasmus Munk Larsen committed Oct 24, 2025

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### Description
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Clarify range...

ComplexQZ would try to apply a Jacobi rotation to an empty block, which triggers a warning in static analyzers, since the corresponding `Eigen::Map` object will contain a `nullptr`.

See merge request !2043