diff --git a/new/build-system.jam b/new/build-system.jam
index 9c423c19c..80c506099 100644
--- a/new/build-system.jam
+++ b/new/build-system.jam
@@ -3,4 +3,14 @@
 #  all copies. This software is provided "as is" without express or implied
 #  warranty, and with no claim as to its suitability for any purpose.
 import project ;
+
+# This rule is just here to suppress a warning generated by Jambase
+# when the build system fails to be found. Using the presence of rules
+# in build-system.jam to check for this is probably ill-advised; we
+# should use GLOB instead. When that happens, __dummy can go away.
+rule __dummy
+{
+    EXIT "don't call this rule" ;
+}
+
 project.load [ PWD ] ;