patch 7.4.1937

Problem:    No test for directory stack in quickfix.
Solution:   Add a test. (Yegappan Lakshmanan)

src/version.c

@@ -753,6 +753,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1937,
 /**/
     1936,
 /**/