message: fix linker issues with g++ and clang-cuda
  g++ expects PIC code, clang-cuda only generates static
diff: @@ -8,4 +8,6 @@ if (GINKGO_BUILD_CUDA AND GINKGO_BUILD_OMP)
  target_link_libraries(custom-matrix-format ginkgo)
  target_include_directories(custom-matrix-format PRIVATE
  ${PROJECT_SOURCE_DIR} ${CMAKE_CURRENT_SOURCE_DIR})
  + # workaround for clang-cuda/g++ interaction
  + set_target_properties(custom-matrix-format PROPERTIES POSITION_INDEPENDENT_CODE ON)
  endif()
  