The pinned termux base image ships libc++ 29. apt's cmake 4.4.4 needs a
newer libc++, but its Depends has no version bound, so apt keeps 29 and
cmake dies at load with an unresolved libc++ symbol. scikit-build-core
reads that as no cmake and compiles one from the PyPI sdist, whose
bootstrap exits 9. That killed the pybind11 build pillow needs, so every
termux .deb build since Oct 3 failed.
Name libc++ in both package lists so apt upgrades it.
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