This patch mimics the behavior of qt.pro, where the module list is
extracted from the .gitmodules file and then topologically sorted
based on the modules dependencies.
This patch also introduces a small check to make sure all the required
dependencies are met and will be built.
Change-Id: Idd3df9b618805ca0b2347eac57aaa39c1bcdb3dd
Reviewed-by: Qt CMake Build Bot
Reviewed-by: Joerg Bornemann <joerg.bornemann@qt.io>
Also import and use ECMOptionalAddSubdirectory.cmake to add other
module's as subdirectories, in case the directories exist. Additionally
this module allows to disable the build of submodules by passing e.g.
BUILD_qtsvg=OFF.
This probably needs more though on how to hande the intermodule dependencies,
but it's a start.
Task-number: QTBUG-75582
Change-Id: Ic3de9711d9b865b2d96bdaee0089f570408b9693
Reviewed-by: Qt CMake Build Bot
Reviewed-by: Cristian Adam <cristian.adam@qt.io>
