--- a/src/zc/buildout/easy_install.py	2013-08-27 22:28:40.233718116 +0200
+++ b/src/zc/buildout/easy_install.py   2013-10-07 00:29:31.077413935 +0200
@@ -227,6 +227,12 @@
 
     def _satisfied(self, req, source=None):
         dists = [dist for dist in self._env[req.project_name] if dist in req]
+        try:
+            dists = ([dist for dist in dists
+                     if dist.precedence == pkg_resources.DEVELOP_DIST]
+                     + [pkg_resources.get_distribution(req.project_name)])
+        except pkg_resources.DistributionNotFound:
+            pass
         if not dists:
             logger.debug('We have no distributions for %s that satisfies %r.',
                          req.project_name, str(req))