Fix building with older Qt

Quotient/events/event.cpp

@@ -25,7 +25,7 @@ void AbstractEventMetaType::addDerived(const AbstractEventMetaType* newType)
         // is not normal, so give as much information as possible to diagnose
         if (QUO_ALARM_X(
                 (*existing)->className == newType->className,
-                QLatin1StringView(newType->className) % " claims '"_L1 % newType->matrixId
+                QString::fromLatin1(newType->className) % " claims '"_L1 % newType->matrixId
                     % "' repeatedly;"
                       " check that it's exported across translation units or shared objects"_L1))
             return; // That situation is very wrong so maybe std::terminate() even?