CMake: Fix rpath-link dependencies when cross-compiling

Private Qt module dependencies of a Qt module are recorded
in the IMPORTED_LINK_DEPENDENT_LIBRARIES property of a Qt module.
This property is used to compute the runtime dependency dir path
to be passed to the linker via the -rpath-link option.

If the referenced target does not exist in the scope where it's
used, no -rpath-link will be generated (or at least that specific
dir path won't be passed).
The linking operation will either fail saying the library is not found,
or a different version of the library might be silently picked up in
the sysroot or other implicit lib dir.

Make sure that QtFooModuleDependencies.cmake calls find_package() for
all Qt module private dependencies (or other Qt provided 3rd party
libs in the Qt6:: namespace) so that the targets are in scope and
IMPORTED_LINK_DEPENDENT_LIBRARIES does its job.

qmake also records the INTERFACE_LINK_LIBRARIES of a private Qt module
as the runtime dependencies of the module.
It's not clear why it does that. A private Qt module is an
INTERFACE_LIBRARY so it shouldn't add any new runtime dependencies.

Nevertheless, the find_package part of that has been recently addressed
in 2b6500cd15c0a41cf3e5eea8178e2044012dbd97 for a different reason.

This change is basically the CMake equivalent of
326b91ea788b013512ae911c51cc19497d88916d

Pick-to: 6.2
Fixes: QTBUG-86533
Change-Id: Iaf514a14acaded4e8752149cca0c159a271be188
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Alexey Edelev <alexey.edelev@qt.io>
Reviewed-by: Joerg Bornemann <joerg.bornemann@qt.io>

0 files changed, 0 insertions, 0 deletions