Enable addition of module using basis_add_subdirectory

[schuhschuh]

Issue by schuhschuh
Friday Apr 01, 2016 at 13:38 GMT
Originally opened as cmake-basis/legacy#562

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Instead of basis_add_module, it should be possible to use basis_add_subdirectory to add a directory that contains a BASIS project module, i.e., a BasisProject.cmake file. In this case, PROJECT_IS_MODULE must be set to TRUE before the add_subdirectory and to FALSE again afterwards. This is useful when specifying a module directory as one of the directories of the project rather than having it as part of the list of modules that can be enabled/disabled (auto-addition of MODULE_<Name> option).