media-sound/cantata uses fontawesome, as installed in /usr/share/cantata/fonts/fontawesome-4.3.0.ttf. Starting cantata though gives the following error: Failed to compute left/right minimum bearings for "FontAwesome". and fails to display most icons, as long as /usr/share/texmf-dist/fonts/type1/public/fontawesome/FontAwesome.pfb from dev-texlive/texlive-fontsextra also exists. Compare: https://github.com/CDrummond/cantata/issues/903
I somehow doubt that dev-tex*/* has anything to do with it. Please check if you have media-fonts/fontawesome installed, and try to run cantata with /usr/share/cantata/fonts/fontawesome-4.3.0.ttf removed.
I do not have media-fonts/fontawesome installed and cantata has actually installed fontawesome-webfont.ttf, not 4.3.0. Now, the following happens with /usr/share/cantata/fonts/fontawesome-webfont.ttf and /usr/share/texmf-dist/fonts/type1/public/fontawesome/FontAwesome.pfb: In place of the icons only a narrow rectangle is drawn and I get the error Failed to compute left/right minimum bearings for "FontAwesome". without /usr/share/cantata/fonts/fontawesome-webfont.ttf but with /usr/share/texmf-dist/fonts/type1/public/fontawesome/FontAwesome.pfb: No icons are drawn, also no rectangle and no error message is given. with /usr/share/cantata/fonts/fontawesome-webfont.ttf but without /usr/share/texmf-dist/fonts/type1/public/fontawesome/FontAwesome.pfb: The icons are drawn correctly and no error message is printed.
Confirm the bug and the relation to /usr/share/texmf-dist/fonts/type1/public/fontawesome/FontAwesome.pfb. This little sample program [1] can be used instead of Cantata to verify the bug. However, I encountered this bug while trying to use FontAwesome icons in a zsh theme and discovered that Konsole displays no icons, while gnome-terminal does. [1] https://github.com/gamecreature/QtAwesome
https://bugreports.qt.io/browse/QTBUG-68853
See also: https://github.com/CDrummond/cantata/issues/903