Added library prefix for assimp.

CMake/ExternalAssimp.cmake

@@ -22,12 +22,12 @@ INSTALL(DIRECTORY ${install_dir}/include/
     DESTINATION ${POLYCODE_DEPS_TOOLS_PREFIX}/Include)
 
 # install debug lib
-INSTALL(FILES ${install_dir}/lib/assimp${CMAKE_STATIC_LIBRARY_SUFFIX} 
+INSTALL(FILES ${install_dir}/lib/${CMAKE_STATIC_LIBRARY_PREFIX}assimp${CMAKE_STATIC_LIBRARY_SUFFIX} 
     DESTINATION ${POLYCODE_DEPS_TOOLS_PREFIX}/Lib/Debug
     CONFIGURATIONS Debug
     RENAME assimpd${CMAKE_STATIC_LIBRARY_SUFFIX})
 
 # install release lib
-INSTALL(FILES ${install_dir}/lib/assimp${CMAKE_STATIC_LIBRARY_SUFFIX} 
+INSTALL(FILES ${install_dir}/lib/${CMAKE_STATIC_LIBRARY_PREFIX}assimp${CMAKE_STATIC_LIBRARY_SUFFIX} 
     DESTINATION ${POLYCODE_DEPS_TOOLS_PREFIX}/Lib/Release
     CONFIGURATIONS Release)