[KDE/Mac] Fwd: Qtbase patch for configurable standard paths

[René J.V. Bertin]

Drafintg a test version with an optional per-call mode override I realised there's another aspect that wasn't ever mentioned before: reentrance. 
Currently QSP is thread-safe because it doesn't have state (right?) or, with my patch, because state is not supposed to change back and forth, let alone inside a QSP call.

A wrapper class that allows a per-call override of the global mode setting would probably require using a QAtomicSomething barrier in the respective QSP calls, which is a drawback (probably not a big one though?).

Your proposition has the advantage that it shouldn't require anything of the sort.

OTOH, how do you propose we tackle ApplicationsLocation? You must remember my "little" run-in with that location. Would adding a location to what usually is a single location (i.e. ${prefix}/share/applications to /Applications) work, with a guarantee that no confusion will ever arise between the different kind of content in those 2 places? Even if that's the case, this is probably a location that does need special treatment for its writable version.
It most definitely isn't true that the actual location doesn't matter for this one, and I'd say that you can hardly get around distinguishing between a native and an XDG-compliant more for this location.

I think we didn't identify other locations with similar requirements when we discussed this, right? 

R.