Add the 'undoreload' option to be able to undo a file reload.
diff --git a/src/option.c b/src/option.c
index 8a3f6b5..2c5e88b 100644
--- a/src/option.c
+++ b/src/option.c
@@ -2655,6 +2655,9 @@
 			    (char_u *)100L,
 #endif
 				(char_u *)0L} SCRIPTID_INIT},
+    {"undoreload",  "ur",   P_NUM|P_VI_DEF,
+			    (char_u *)&p_ur, PV_NONE,
+			    { (char_u *)10000L, (char_u *)0L} SCRIPTID_INIT},
     {"updatecount", "uc",   P_NUM|P_VI_DEF,
 			    (char_u *)&p_uc, PV_NONE,
 			    {(char_u *)200L, (char_u *)0L} SCRIPTID_INIT},