diff --git a/engine/gl/gl_vidnull.c b/engine/gl/gl_vidnull.c
index 8524ed614..88ec841e0 100644
--- a/engine/gl/gl_vidnull.c
+++ b/engine/gl/gl_vidnull.c
@@ -83,6 +83,9 @@ void IN_ReInit(void)
 
 void IN_Init(void)
 {
+#ifdef IN_XFLIP
+	Cvar_Register (&in_xflip, "Input Controls");
+#endif
 }
 
 void IN_Shutdown(void)
diff --git a/engine/sw/vid_null.c b/engine/sw/vid_null.c
index c3dc0a0a6..46728137e 100644
--- a/engine/sw/vid_null.c
+++ b/engine/sw/vid_null.c
@@ -72,6 +72,9 @@ void IN_ReInit(void)
 
 void IN_Init(void)
 {
+#ifdef IN_XFLIP
+	Cvar_Register (&in_xflip, "Input Controls");
+#endif
 }
 
 void IN_Shutdown(void)