This change introduces new behavior to error out when configuring user
projects if the CMake version used is too old for Qt to work with.
The main motivator is the requirement of new CMake features to ensure
object libraries are placed in the proper place on the link line in
static builds.
The minimum CMake version is computed based on whether Qt was
configured as shared or static libraries.
At the moment the required versions for building and using Qt are the
same.
The minimum versions are defined in qtbase/.cmake.conf in the
following variables
QT_SUPPORTED_MIN_CMAKE_VERSION_FOR_BUILDING_QT_SHARED
QT_SUPPORTED_MIN_CMAKE_VERSION_FOR_BUILDING_QT_STATIC
QT_SUPPORTED_MIN_CMAKE_VERSION_FOR_USING_QT_SHARED
QT_SUPPORTED_MIN_CMAKE_VERSION_FOR_USING_QT_STATIC
Qt Packagers can disable the version check when configuring Qt
by setting
QT_FORCE_MIN_CMAKE_VERSION_FOR_BUILDING_QT and
QT_FORCE_MIN_CMAKE_VERSION_FOR_USING_QT.
In this case it is the packagers responsibility to ensure such a Qt
works correctly with the specified CMake version.
User projects can also set QT_FORCE_MIN_CMAKE_VERSION_FOR_USING_QT
to disable the version check. Then it's the project's developer
responsibility to ensure such a Qt works correctly.
No official support is provided for these cases.
Implementation notes.
The versions required to build Qt are stored in
QtBuildInternalsExtra.cmake
whereas the versions required to use Qt are stored in a new
QtConfigExtras.cmake.
Also the policy range variables stored in
QtBuildInternalsExtra.cmake are now regular variables instead of cache
variables, to properly allow overrides per-repository.
Some renaming of functions and variables was done for a bit more
clarity and easier grep-ability.
Pick-to: 6.2
Task-number: QTBUG-95018
Change-Id: I4279f2e10b6d3977319237ba21e2f4ed676aa48b
Reviewed-by: Alexey Edelev <alexey.edelev@qt.io>
Reviewed-by: Joerg Bornemann <joerg.bornemann@qt.io>
