proof-set-queue-endpoints: only use undo-discarding function if

undo-make-selective-list is available (not on XEmacs).

1 files changed, 9 insertions, 3 deletions

diff --git a/generic/proof-script.el b/generic/proof-script.el
index 7ebae6b8..3cd6a968 100644
--- a/generic/proof-script.el
+++ b/generic/proof-script.el
@@ -202,13 +202,19 @@ scripting buffer may have an active queue span.")
        (proof-span-read-only proof-locked-span))))
 
    
-(defsubst proof-set-queue-endpoints (start end)
-  "Set the queue span to be START, END."
+(cond
+ ((boundp 'undo-make-selective-list)
+  (defsubst proof-set-queue-endpoints (start end)
+  "Set the queue span to be START, END. Discard undo for edits before END."
   (unless (or (eq buffer-undo-list t) 
 	      proof-allow-undo-in-read-only)
     (setq buffer-undo-list 
 	  (undo-make-selective-list end (point-max))))
-  (span-set-endpoints proof-queue-span start end))
+  (span-set-endpoints proof-queue-span start end)))
+ (t
+  (defsubst proof-set-queue-endpoints (start end)
+  "Set the queue span to be START, END."
+  (span-set-endpoints proof-queue-span start end))))
 
 (defsubst proof-set-locked-endpoints (start end)
   "Set the locked span to be START, END."