diff --git a/src/cuirass/base.scm b/src/cuirass/base.scm
index 5a0c826..99a17fa 100644
--- a/src/cuirass/base.scm
+++ b/src/cuirass/base.scm
@@ -632,6 +632,21 @@ This procedure is meant to be called at startup."
      db "UPDATE Builds SET status = 4 WHERE status = -2 AND timestamp < "
      (- (time-second (current-time time-utc)) age) ";")))
 
+(define (partition pred lst)
+  ;; Scheme implementation of SRFI-1 'partition' so stack activations can be
+  ;; captured via 'abort-to-prompt'.
+  (let loop ((lst   lst)
+             (pass '())
+             (fail '()))
+    (match lst
+      (()
+       (values (reverse pass) (reverse fail)))
+      ((head . tail)
+       (let ((pass? (pred head)))
+         (loop tail
+               (if pass? (cons head pass) pass)
+               (if pass? fail (cons head fail))))))))
+
 (define (restart-builds)
   "Restart builds whose status in the database is \"pending\" (scheduled or
 started)."