sixtracklib/cuda: attempts to fix linking issue with CMake > 3.14.x

Backported from #PR130

- The flag CUDA_RESOLVE_DEVICE_SYMBOLS should be enabled by default on
  shared libraries like SixTrackLib. The property does not work on
  OBJECT libraries like sixtrack_cuda_device. It seems that starting
  with cmake 3.15, cmake did not pick up the property for the resulting
  compound SHARED library just by inferring the dependency on the CUDA
  device part.

  This fix attempts to rectify this by adding the property explicitly
  to the SHARED sixtracklib library if the sixtrack_cuda_device
  target is present.

  Tested on CMake 3.14, 3.16 und 3.18 -> seems to work

- Note: this would fix issue SixTrack#109 but more investigation is required whether
  this solves all problems encountered therein

sixtracklib/CMakeLists.txt

@@ -94,6 +94,10 @@ set_target_properties( sixtrack PROPERTIES
     LINKER_LANGUAGE C POSITION_INDEPENDENT_CODE ON C_STANDARD 99
     DEBUG_POSTFIX d C_STANDARD_REQUIRED ON )
 
+if( TARGET sixtrack_cuda_device )
+    set_target_properties( sixtrack PROPERTIES CUDA_RESOLVE_DEVICE_SYMBOLS ON )
+endif()
+
 target_compile_options( sixtrack PRIVATE
     ${SIXTRACKLIB_C99_FLAGS} ${SIXTRACKLIB_CPU_FLAGS}
     ${SIXTRACKL_C99_AUTOVEC_FLAGS} )

sixtracklib/cuda/CMakeLists.txt

@@ -133,14 +133,10 @@ add_library( sixtrack_cuda_device OBJECT
 target_compile_definitions( sixtrack_cuda_device
     PUBLIC ${SIXTRACKL_CUDA_DEVICE_DEFINITIONS} )
 
-set_target_properties( sixtrack_cuda_device PROPERTIES POSITION_INDEPENDENT_CODE ON )
-set_target_properties( sixtrack_cuda_device PROPERTIES LINKER_LANGUAGE C )
-set_target_properties( sixtrack_cuda_device PROPERTIES CXX_STANDARD 11 )
-set_target_properties( sixtrack_cuda_device PROPERTIES CXX_STANDARD_REQUIRED ON )
-set_target_properties( sixtrack_cuda_device PROPERTIES CUDA_SEPARABLE_COMPILATION  ON  )
-set_target_properties( sixtrack_cuda_device PROPERTIES CUDA_RESOLVE_DEVICE_SYMBOLS OFF )
-set_target_properties( sixtrack_cuda_device PROPERTIES CUDA_STANDARD 11 )
-set_target_properties( sixtrack_cuda_device PROPERTIES CUDA_STANDARD_REQUIRED 11 )
+set_target_properties( sixtrack_cuda_device PROPERTIES
+    POSITION_INDEPENDENT_CODE ON LINKER_LANGUAGE C CXX_STANDARD 11
+    CXX_STANDARD_REQUIRED ON CUDA_SEPARABLE_COMPILATION  ON
+    CUDA_RESOLVE_DEVICE_SYMBOLS ON CUDA_STANDARD 11 CUDA_STANDARD_REQUIRED 11 )
 
 target_include_directories( sixtrack_cuda_device PRIVATE ${CMAKE_SOURCE_DIR} )