diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 35ae3074a972015c37dea270b53e1e90c1fbc347..c5180ba3f1debf3ccba4b4de40f6df915f622736 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -658,8 +658,10 @@ set(OPTIONAL_INCLUDES)
 macro(append_optional_libs targets)
   foreach(_target ${targets})
     get_target_property(_link_libraries ${_target} INTERFACE_LINK_LIBRARIES)
+    if(_link_libraries)
+      list(APPEND OPTIONAL_LIBS ${_link_libraries})
+    endif()
     get_target_property(_include_dirs ${_target} INTERFACE_INCLUDE_DIRECTORIES)
-    list(APPEND OPTIONAL_LIBS ${_link_libraries})
     if(_include_dirs)
       list(APPEND OPTIONAL_INCLUDES ${_include_dirs})
     endif()