patch 7.4.1399
Problem:    The MS-DOS code does not build.
Solution:   Remove the old MS-DOS code.
diff --git a/src/ex_cmds.c b/src/ex_cmds.c
index 78d9f95..a2186b2 100644
--- a/src/ex_cmds.c
+++ b/src/ex_cmds.c
@@ -1925,14 +1925,10 @@
 #ifdef UNIX
 				    shortname,
 #else
-# ifdef SHORT_FNAME
-				    TRUE,
-# else
-#  ifdef FEAT_GUI_W32
+# ifdef FEAT_GUI_W32
 				    gui_is_win32s(),
-#  else
+# else
 				    FALSE,
-#  endif
 # endif
 #endif
 				    fname,