The hyphenation inside the calibre is done via the javascript magick, so the actual hyphenation is peformed by the webkit. However if the qtwebkit is built without icu flag, the hyphenation fails siliently. Seem to be like an easy fix.
Current calibre ebuild does not list Qtwebkit as dependency. Is this report about a missing dependency (as compared to missing use dep) or a version that has since left Portage?
ping.
The Qtwebkit dependency is indirect, via dev-python/PyQt5[webkit]. Since PyQt5 doesn't have an icu USE flag, we'll have to add a direct dependency on dev-qt/qtwebkit. Upstream has a qtwebkit dependency listed here: https://github.com/kovidgoyal/build-calibre/blob/master/scripts/sources.json
Qtwebkit is treecleaned, calibre has used webengine instead for a long time. And it looks like even qtwebkit only had *old* versions of it contain a USE flag for icu. This error cannot happen anymore as described here. The tech stack is too different. If there is still an issue, please open a new bug.
