BUG: Fix ctkMacroGetAllNonCTKTargetLibraries

Do not attempt to remove all_ctk_libraries from _tmp_list when
all_ctk_libraries is empty.

CMake/ctkMacroTargetLibraries.cmake

@@ -125,7 +125,9 @@ ENDMACRO()
 MACRO(ctkMacroGetAllNonCTKTargetLibraries all_target_libraries varname)
   ctkMacroGetAllCTKTargetLibraries("${all_target_libraries}" all_ctk_libraries)
   SET(_tmp_list ${all_target_libraries})
-  LIST(REMOVE_ITEM _tmp_list ${all_ctk_libraries})
+  IF("${all_ctk_libraries}")
+    LIST(REMOVE_ITEM _tmp_list ${all_ctk_libraries})
+  ENDIF()
   SET(${varname} ${_tmp_list})
   #MESSAGE(STATUS varname:${varname}:${${varname}})
 ENDMACRO()