--- a/plugins/vnc/vinagre-vnc-connection.c
+++ b/plugins/vnc/vinagre-vnc-connection.c
@@ -27,6 +27,8 @@
 #include "vinagre-vnc-connection.h"
 #include "vinagre-vala.h"
 
+gboolean scaling_command_line;
+
 struct _VinagreVncConnectionPrivate
 {
   gchar    *desktop_name;
--- a/plugins/vnc/vinagre-vnc-connection.h
+++ b/plugins/vnc/vinagre-vnc-connection.h
@@ -26,7 +26,7 @@
 
 G_BEGIN_DECLS
 
-gboolean scaling_command_line;
+extern gboolean scaling_command_line;
 
 #define VINAGRE_TYPE_VNC_CONNECTION             (vinagre_vnc_connection_get_type ())
 #define VINAGRE_VNC_CONNECTION(obj)             (G_TYPE_CHECK_INSTANCE_CAST ((obj), VINAGRE_TYPE_VNC_CONNECTION, VinagreVncConnection))