diff --git a/cmake/CMakeLists.txt b/cmake/CMakeLists.txt
index 2f363030..34a1083b 100644
--- a/cmake/CMakeLists.txt
+++ b/cmake/CMakeLists.txt
@@ -449,8 +449,8 @@ if (WIN32)
   # bus-test expects a non empty string
   set (DBUS_USER "Administrator")
 else (WIN32)
-  option (DBUS_SYSTEM_BUS_DEFAULT_ADDRESS "system bus default address" "unix:tmpdir=")
-  option (DBUS_SESSION_BUS_DEFAULT_ADDRESS "session bus default address" "unix:path=${DBUS_SESSION_SOCKET_DIR}")
+  set (DBUS_SYSTEM_BUS_DEFAULT_ADDRESS "unix:tmpdir=" CACHE STRING "system bus default address")
+  set (DBUS_SESSION_BUS_DEFAULT_ADDRESS "unix:path=${DBUS_SESSION_SOCKET_DIR}" CACHE STRING "session bus default address")
   set (sysconfdir "")
   set (configdir ${sysconfdir}/dbus-1 )
   set (DBUS_SYSTEM_CONFIG_FILE  ${configdir}/system.conf)