if you try to build udisks w/libgudev-150 installed, it'll fail: checking for GUDEV... no configure: error: Package requirements (gudev-1.0 >= 165) were not met: No package 'gudev-1.0' found the ebuild should depend on that version rather than none at all.
commit cdaaec7f32ae7b788290211836c7d07be95da57c sys-fs/udisks: add missing version specifier, bug #559732. Add missing gtk-doc-am dependency for documentation relinking. Thanks for reporting.