So far we always recommended that developers set CMAKE_PREFIX_PATH to
point to the location of the Qt installation so that Qt packages are
found by CMake.
In Qt5 one could also set the Qt5_DIR variable to $qt/lib/cmake/Qt5
to allow the following signature to work:
find_package(Qt5 COMPONENTS Core)
This was not sufficient in Qt6 because the CoreTools dependency would
not be found.
Fix this by also looking into the parent folder of
CMAKE_CURRENT_LIST_DIR as well as _qt_cmake_dir, like we already do
for regular non-Tools packages in _qt_internal_find_dependencies.
Note that setting Qt6_DIR is not sufficient for cross-compilation if
the qt.toolchain.cmake file is not used.
Aside from platform specific options that would have to be passed
manually to CMake (like -DCMAKE_SYSTEM_NAME=iOS for iOS) and
passing a QT_HOST_PATH value, the code would also need to be
adapted to do the necessary CMAKE_FIND_ROOT_PATH manipulations
to ensure that dependent packages are found.
Pick-to: 6.4
Task-number: QTBUG-97615
Change-Id: I10c419632d43bb929e184bab3b9d3d27a35ea87a
Reviewed-by: Jörg Bornemann <joerg.bornemann@qt.io>
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