Unmerged branches in origin/tags/

Unmerged branches that do not match releases/, tags/, personal/, Txxx-, or bug-xxx-

Extracted from the huge list above.

Pushed new branch T27025-FixDocumentationWarnings.

Too meta, fixed a few warnings, though.

Pushed new branch T27024-FixSpectralUnmixingTest.

Here's my CMake merge request: https://gitlab.kitware.com/cmake/cmake/merge_requests/4258

In CMake, Source/CTest/cmCTestTestHandler.cxx, cmCTestTestHandler::ProcessHandler(), there is a check if the sum of passed and failed tests equal zero. After another pre-check (see below), "No tests were found!!!" is logged as ERROR_MESSAGE. In Source/cmCTest.cxx, cmCTest::Log(), cmSystemTools::SetErrorOccured() is called if the log type is ERROR_MESSAGE.

Reverted the removal as CTest still fails, probably because of no tests in superbuild projects. I think the best way to solve this is to contribute to CMake.

Pushed new branch T27022-RemoveUnusedSubprojects.

I have introduced a new superbuild and MITK-build advanced cache variable called MITK_XVFB_TESTING. If switched on, it will prepend testdriver calls with xvfb-run --auto-servernum resulting in having a virtual frame buffer available for rendering tests. This is useful in headless systems like continuous integration clients. Works for Linux. To install xvfb call sudo apt install xvfb.

Pushed new branch T27019-RenderingTestsOnLinux.

https://gitlab.kitware.com/cmake/cmake/issues/20165

For now, re-introduce a check for OpenGL support until we found a solution.

Test now do run on Windows but they fail because of OpenGL context creation issues. I guess it has something to do with using the Windows client in "headless" mode.

Pushed new branch T26992-FixRenderingTestHelper.