Upstream changes to the build system required adjusting many packages'
dependencies. On the Nixpkgs side, we no longer propagate the dependency
on cmake (to reduce closure size), so downstream dependencies had to be
adjusted for most packages that depend on kdelibs.
polkit-qt-1 is upgraded to the latest version, which supports Qt 5. The
attributes are also renamed to differentiate the Qt 4 and Qt 5
branches. The prior naming scheme differentiated between polkit-qt-1 and
polkit-qt, but we no longer package the latter.
