[Development] Q_COMPILER_VARIADIC_TEMPLATES since Qt 5.7

[Александр Волков]

Hi,

It is stated in https://codereview.qt-project.org/#/c/168057/ that 
Q_COMPILER_VARIADIC_TEMPLATES is required since Qt 5.7.
It is true? Can I use QOverload which depends on it ( 
https://codereview.qt-project.org/#/c/180525/ ) ?

BR,
Alexander.