qt5-qtwebengine on macOS 10.13, Xcode version

[Ken Cunningham]

> WARNING: QtWebEngine requires at least version 10.0.0, but using Xcode version 9.4.1.

Should be a ticket if not one already I guess.

I was wondering when we updated qt5 if that might happen to those who have held back their Xcode on 10.13 systems. All my systems use the current Xcodes.

Could you try forcing a macports-clang compiler like 9.0 and see if that works? If it does, we might get past this rather more easily...otherwise as a local workaround you might change the xcode used for this build, then change back if feel you must...obviously not a buildbot fix though.

However, I would float the idea it's time the buildbot and all 10.13 users moved to Xcode 10.

Xcode 10's issues have largely been worked around by this point it seems, although there a couple of stragglers still.

Ken