Eigen 5.x compatibility

[speth]

This should be the necessary changes for compatibility with the recent Eigen 5.0 release, per https://github.com/conda-forge/eigen-feedstock/blob/b23c3f3f4527e8b3cbcdd496dae888c358489244/recipe/README.md.

Checklist

• Used a personal fork of the feedstock to propose changes
• Bumped the build number (if the version is unchanged)
• Re-rendered with the latest conda-smithy (Use the phrase @conda-forge-admin, please rerender in a comment in this PR for automated rerendering)
• Ensured the license file is being packaged.

[conda-forge-admin]

Hi! This is the friendly automated conda-forge-linting service.

I wanted to let you know that I linted all conda-recipes in your PR (recipe/meta.yaml) and found some lint.

Here's what I've got...

For recipe/meta.yaml:

• ❌ You are setting MACOSX_SDK_VERSION below c_stdlib_version, in conda_build_config.yaml which is not possible! Please ensure MACOSX_SDK_VERSION is at least c_stdlib_version (you can leave it out if it is equal).
  If you are not setting c_stdlib_version yourself, this means you are requesting a version below the current global baseline in conda-forge (11.0). If this is the intention, you also need to override c_stdlib_version and MACOSX_DEPLOYMENT_TARGET locally.

For recipe/meta.yaml:

• ℹ️ The recipe is not parsable by parser conda-souschef (grayskull). This parser is not currently used by conda-forge, but may be in the future. We are collecting information to see which recipes are compatible with grayskull.
• ℹ️ The recipe is not parsable by parser conda-recipe-manager. The recipe can only be automatically migrated to the new v1 format if it is parseable by conda-recipe-manager.

_{This message was generated by GitHub Actions workflow run https://github.com/conda-forge/conda-forge-webservices/actions/runs/22689542872. Examine the logs at this URL for more detail.}

[speth]

• ❌ You are setting MACOSX_SDK_VERSION below c_stdlib_version, in conda_build_config.yaml which is not possible! Please ensure MACOSX_SDK_VERSION is at least c_stdlib_version (you can leave it out if it is equal).
  If you are not setting c_stdlib_version yourself, this means you are requesting a version below the current global baseline in conda-forge (11.0). If this is the intention, you also need to override c_stdlib_version and MACOSX_DEPLOYMENT_TARGET locally.

I think this report is incorrect -- our meta.yaml does not specify either MACOSX_SDK_VERSION or c_stdlib_version -- the only mentions of these variables are in the auto-generated files in the .ci_support directory, and even then they are both set equal to 11.0 for all macOS builders.

[speth]

The errors for the Python 3.14 builds are related to an issue that's already fixed on the Cantera main branch (see Cantera/cantera#2063), and staged for a 3.2.1 maintenance release (Cantera/cantera#2092). So we either need to do one of the following:

• apply that patch here
• move ahead with the 3.2.1 maintenance release
• Pin to numpy < 2.4.0 for now

[bryanwweber]

Thanks @speth. My inclination is to push out 3.2.1 to include the fix