Add the 'undoreload' option to be able to undo a file reload.
diff --git a/src/memline.c b/src/memline.c
index 0f7b1d1..9fe9439 100644
--- a/src/memline.c
+++ b/src/memline.c
@@ -2529,7 +2529,7 @@
     int		newfile;	/* flag, see above */
 {
     /* When starting up, we might still need to create the memfile */
-    if (curbuf->b_ml.ml_mfp == NULL && open_buffer(FALSE, NULL) == FAIL)
+    if (curbuf->b_ml.ml_mfp == NULL && open_buffer(FALSE, NULL, 0) == FAIL)
 	return FAIL;
 
     if (curbuf->b_ml.ml_line_lnum != 0)
@@ -3078,7 +3078,7 @@
 	return FAIL;
 
     /* When starting up, we might still need to create the memfile */
-    if (curbuf->b_ml.ml_mfp == NULL && open_buffer(FALSE, NULL) == FAIL)
+    if (curbuf->b_ml.ml_mfp == NULL && open_buffer(FALSE, NULL, 0) == FAIL)
 	return FAIL;
 
     if (copy && (line = vim_strsave(line)) == NULL) /* allocate memory */