Currently, there is this in the ebuild: echo "UI_TYPE = qt4" >> makefiles/target.mk But, qt4 is not the only option, gtk is another: echo "UI_TYPE = gtk" >> makefiles/target.mk Please utilize the qt and gtk USE flags. Reproducible: Always
From https://fbreader.org/content/fbreader-beta-linux-desktop Since version 0.99.0 FBReader requires Qt4 library. gtk+ version is not supported at this moment. We plan to release versions for Windows and MacOS later this year.