Our qhull ebuild goes out of the way to install the deprecated libqhull.so. Ionen added this to the build in January (commit: 02bc620cff) with the comment "deprecated, but needed by matplotlib." But I think that now, all versions of matplotlib in the tree use only the re-entrant libqhull_r.so library: https://github.com/matplotlib/matplotlib/commit/d81d15d368ec8b7fbdd3c0450d7d3ee96641ffe1 Is it safe to drop the deprecated one at this point?
More precisely sam re-added it, but later I summarized what it installed to explain the unfortunate need for static-libs alongside it. Back then it was re-added bit in a rush because it broke matplotlib, but would need to check all revdeps. I didn't check all but, for two, sci-libs/plplot-5.15.0-r102 and sci-visualization/gr-0.53.0 are using libqhull.so.8.0 for me.
(In reply to Ionen Wolkens from comment #1) > > I didn't check all but, for two, sci-libs/plplot-5.15.0-r102 and > sci-visualization/gr-0.53.0 are using libqhull.so.8.0 for me. OK, it's no big deal to just close this if something still needs the old library. We're getting ready to let SageMath use a system copy of qhull with its vendored matplotlib, so I was just poking around to see what shape qhull is in.