* gnu/packages/qt.scm (qt): Update to 5.5.0. Update download location.
Drop patch and snippet.
[arguments]: Add configure flag to drop qtwebengine module bundling
chromium.
[native-inputs]: Drop ninja, needed only for qtwebengine.
[inputs]: Add harfbuzz to avoid use of bundled copy.
(qt-4)[inputs]: Remove inherited harfbuzz again.
* gnu/packages/patches/qt5-conflicting-typedefs.patch: Delete file.
* gnu-system.am (dist_patch_DATA): Unregister patch.
* gnu/packages/patches/qt5-runpath.patch: Adapt patch.