-Wno-non-virtual-dtor

[Tor Lillqvist]

Hmm, now that the reason for using  -Wno-non-virtual-dtor has been
documented (760e0d2d7329ca6fc00a8439715bae38becb168a ), I wonder,
should we globally then also turn off the corresponding MSVC warning?

That would be kinda predictable (from a "the usual waste of time"
point of view), as I and others have committed over times dozens of
WaE fixes for this very issue... (I.e. added a virtual no-op
destructor in most cases).

Or does gcc and MSVC warn for different cases of lack of virtual
destructor? Is it certain that in all cases this warning is bogus, in
both the gcc and MSVC cases?

--tml