Index: python.jam
===================================================================
--- python.jam	(revision 43564)
+++ python.jam	(working copy)
@@ -115,7 +115,11 @@
     # environment variable, set by run-pyd. For example, pythonpath can be used
     # to access Python modules that are part of the product being built, but
     # are not installed in the development system's default paths.
-    feature.feature pythonpath : : free optional path ;
+    if ! $($(.project).pythonpath)
+    {
+        $(.project).pythonpath = defined ;
+        feature.feature pythonpath : : free optional path ;
+    }
 
     project.pop-current ;
 }