[dev-qt/qtdemo:4] Remove bogus dependency on qt3support.

Thanks to Rafał Mużyło in bug 510042 comment #2.

Package-Manager: portage-2.2.10
[dev-qt/qtsql:4] src.pro and tools.pro are not used.

Package-Manager: portage-2.2.10
[dev-qt/qtmultimedia:4] src.pro is not used.

Package-Manager: portage-2.2.10
[dev-qt/qthelp:4] Remove obsolete workaround.

It was needed to build the assistant binary,
which is now in a separate package.

Package-Manager: portage-2.2.10
[dev-qt/qthelp:4] Minor cleanup.

Package-Manager: portage-2.2.10
[dev-qt/qtgui:4] Add slot operator to libmng dependency.

Package-Manager: portage-2.2.10