There's a merged pull request on the void-packages repository

musl: backport qsort_r.
https://github.com/void-linux/void-packages/pull/42425

Description:
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#### Testing the changes
- I tested the changes in this PR: **briefly** (built and ran checks for tofi, but since my system is glibc, I can't actually run something to test this)

Required for #42416.

@Gottox (mistakenly pinged ericonr first, sorry for that)

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