Fix build with `-DBUILD_TESTING=OFF`
Fix build with -DBUILD_TESTING=OFF
cmake -DBUILD_TESTING=OFF ..
...
CMake Error at kdevplatform/cmake/modules/KDevPlatformMacros.cmake:124 (add_library):
Target "kdevcustombuildsystem" links to target "KDev::Tests" but the target
was not found. Perhaps a find_package() call is missing for an IMPORTED
target, or an ALIAS target is missing?
Call Stack (most recent call first):
plugins/custom-buildsystem/CMakeLists.txt:21 (kdevplatform_add_plugin)
-- Generating done
CMake Generate step failed. Build files cannot be regenerated correctly.