Enable linux ppc64le builds without Embree

[jeongseok-meta]

Summary

• enable five linux-ppc64le variants
• disable only the optional Embree module on PPC64LE
• preserve core, CGAL, TetGen, and Triangle modules
• document the exact removal condition for the platform workaround
• bump the build number and rerender with conda-smithy 2026.8.9

Why

The previous PPC attempt reached bundled Embree 4.4.0, which passed x86-only -msse2 to the PowerPC compiler. Embree documents support for x86 and Arm, not PPC64LE. libigl already exposes LIBIGL_EMBREE, so disabling that optional module only on PPC is narrower and more accurate than patching Embree to claim unsupported architecture coverage.

Prior failure: https://github.com/jeongseok-meta/igl-feedstock/actions/runs/26786519218/job/78963467294

Validation

• recipe lint passes
• canonical rerender is idempotent
• all five PPC Python variants render and solve
• a full Python 3.12 PPC cross-build passed and produced igl-2.6.1-py312h2b893b7_5.conda
• the package contains core, CGAL, TetGen, and Triangle modules and no Embree module
• the installed-package import test passes under QEMU with the PPC sysroot
• current-head GitHub Actions, Azure, and linter checks all pass

Checklist

• Used a personal fork of the feedstock to propose changes
• Bumped the build number
• Re-rendered with the latest conda-smithy
• Ensured the license file is being packaged

[conda-forge-admin]

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

I just wanted to let you know that I linted all conda-recipes in your PR (recipe/recipe.yaml) and found it was in an excellent condition.