Merge topic 'cxxmodules-export-dirs-with-prefix'

42654cc818 Tests/CXXModules: add tests for modules with include requirements
7217cb78cf Tests/CXXModules: relax line number matching in stderr
b3d1bbbbcc cmExportFileGenerator: relocate include directories for C++ modules
349ff8b080 cmGeneratorTarget: remove not-INTERFACE assertion
681a763425 cmGeneratorTarget: use a character literal

Acked-by: Kitware Robot <kwrobot@kitware.com>
Acked-by: buildbot <buildbot@kitware.com>
Merge-request: !8838