diff --git a/CMakeLists.txt b/CMakeLists.txt
index edb1cec21..6f513c2bc 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1239,7 +1239,9 @@ _add_if("SCP"           USE_LIBSSH2)
 _add_if("SFTP"          USE_LIBSSH2)
 _add_if("RTSP"          NOT CURL_DISABLE_RTSP)
 _add_if("RTMP"          USE_LIBRTMP)
-list(SORT _items)
+if(_items)
+  list(SORT _items)
+endif()
 string(REPLACE ";" " " SUPPORT_PROTOCOLS "${_items}")
 message(STATUS "Enabled protocols: ${SUPPORT_PROTOCOLS}")