Require more of the C++11 Standard Library

Since libstdc++ builds on OS X and QNX 6.5 are no longer supported,
simply require <initializer_list> and std::move in order to claim C++11
support works.

The minimum OS X versions need to be fixed elsewhere.

Change-Id: Ib056b47dde3341ef9a52ffff13ef1d2ac3923f5c
Reviewed-by: Marc Mutz <marc.mutz@kdab.com>
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@theqtcompany.com>
Reviewed-by: Jake Petroules <jake.petroules@petroules.com>
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@theqtcompany.com>
Reviewed-by: Rafael Roquetto <rafael.roquetto@kdab.com>