[F] Not set option-variable (only define for compilation was set.

[F] For adding library can not be used TARGET_LINK_LIBRARIES

code/CMakeLists.txt

@@ -737,7 +737,8 @@ SOURCE_GROUP( open3dgc FILES ${open3dgc_SRCS})
 # has implementation for different platforms: WIN32, __MACH__ and other ("else" block).
 FIND_PACKAGE(RT QUIET)
 IF (RT_FOUND OR MSVC)
-  ADD_DEFINITIONS( -DASSIMP_IMPORTER_GLTF_USE_OPEN3DGC )
+  SET( ASSIMP_IMPORTER_GLTF_USE_OPEN3DGC 1 )
+  ADD_DEFINITIONS( -DASSIMP_IMPORTER_GLTF_USE_OPEN3DGC=1 )
   IF (NOT RT_FOUND)
 	SET (RT_LIBRARY "")
   ENDIF (NOT RT_FOUND)
@@ -873,7 +874,7 @@ endif (UNZIP_FOUND)
 
 # Add RT-extension library for glTF importer with Open3DGC-compression.
 IF (RT_FOUND AND ASSIMP_IMPORTER_GLTF_USE_OPEN3DGC)
-  TARGET_LINK_LIBRARIES(assimp ${RT_LIBRARY})
+  SET_PROPERTY(TARGET assimp APPEND PROPERTY LINK_FLAGS ${RT_LIBRARY})
 ENDIF (RT_FOUND AND ASSIMP_IMPORTER_GLTF_USE_OPEN3DGC)
 
 INSTALL( TARGETS assimp