patch 8.0.1480: patch missing change

Problem:    Patch missing change.
Solution:   Add missing change.
diff --git a/src/evalfunc.c b/src/evalfunc.c
index 02618d7..a19f706 100644
--- a/src/evalfunc.c
+++ b/src/evalfunc.c
@@ -7977,7 +7977,7 @@
 #ifdef FEAT_INS_EXPAND
 	    if (ins_compl_active())
 		buf[1] = 'c';
-	    else if (ctrl_x_mode == 1)
+	    else if (ctrl_x_mode_not_defined_yet())
 		buf[1] = 'x';
 #endif
 	}