Overload the binary QSet operators |, &, + and - for rvalue LHSs, so
chained operations like e.g. in qgesturemanager.cpp:
QSet<QGesture *> endedGestures =
finishedGestures + canceledGestures + undeliveredGestures + maybeToCanceledGestures;
become as efficient as chained op+= calls.
Make the operators hidden friends as a drive-by.
[ChangeLog][QtCore][QSet] The binary operators &, |, + and - are now
hidden friends, and chaining them has been made a lot more efficient.
Change-Id: I55d2247b11d088eb1ef88608f89d2bf9e1daeb58
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
05888490db