When building Qt Creator with MSVC, this is the only warning I get:
  warning: C4309: 'initializing': truncation of constant value

It would be great to silence it.

MSVC supports the "i8" literal extension, which would be fancier than
the cast, here. But I don't know what other compilers think of it.

Change-Id: I3f1bb4f58f6ab378cbeb44a667aebc5ddee25eec
Reviewed-by: Ulf Hermann <ulf.hermann@qt.io>