--- a/mercurial/configitems.py	Wed Jun 28 13:25:33 2017 +0200
+++ b/mercurial/configitems.py	Wed Jun 28 13:37:59 2017 +0200
@@ -62,6 +62,9 @@
 coreconfigitem('devel', 'bundle2.debug',
     default=False,
 )
+coreconfigitem('devel', 'check-locks',
+    default=False,
+)
 coreconfigitem('patch', 'fuzz',
     default=2,
 )