Consider the following situation: There are CMake tests in
qttools/tests/auto/cmake that configure and build CMake test projects,
essentially as external projects. One of those test projects does
find_package(Qt6 COMPONENTS LinguistTools). This call fails in a prefix
build, because Qt6LinguistToolsConfig.cmake is not installed yet. It
merely exists in qttools-build/lib/cmake/Qt6LinguistTools.
We must adjust CMAKE_PREFIX_PATH to be able to find Qt6LinguistTools. We
also must adjust QT_ADDITIONAL_PACKAGES_PREFIX_PATH to be able to find
the LinguistTools component of the Qt6 package.
Use the prefixes setup from the support for building examples as
external projects and use it for CMake test projects as well.
Task-number: QTBUG-84884
Change-Id: I1bd5d5084cf931196bdb014cd75ca7578cd9decb
Reviewed-by: Alexey Edelev <alexey.edelev@qt.io>
Reviewed-by: Alexandru Croitor <alexandru.croitor@qt.io>
