The install-time code path that's supposed to propagate and install the
metatypes files was never executed, because of a wrong
PARENT_SCOPE assignment and because the code was overriding the meta
type file name retrieved from a property with an empty non-existent
argument.
This caused build failures in qtdeclarative when qmlcachegen generated
invalid cpp code without having access to the qtbase foreign types.
This only happened in prefix builds.
Use the appropriate variable for the PARENT_SCOPE assignment and
remove the incorrect file name assignment.
Amends c45c32af32
Task-number: QTBUG-115152
Change-Id: I120d53d44382a1ac6f62792ec1620add3e7b136c
Reviewed-by: Amir Masoud Abdol <amir.abdol@qt.io>
bc2ae5a708