Suppress eager 'develop = .'.

We need to set up an interpreteer copy which has 'persistent' already
installed, to prevent the on-demand eggs for 'persistent' and
'zope.interface' from screwing up the rest of the buildout.

CHANGES.txt

@@ -5,6 +5,9 @@
 4.0.4 (unreleased)
 ------------------
 
+- Accomodate buildout to the fact that we no longer bundle a copy
+  of 'persistent.h'.
+
 - Fix test failures on Windows:  no longer rely on overflows from 
   ``sys.maxint``.
 

buildout.cfg

 [buildout]
-develop = . 
+eggs =
+    persistent
+    zope.interface
 parts =
+    w_persistent
+    develop
     test
     test_w_zodb
     scripts
 
+[w_persistent]
+# Generate an interpreter w/ persistent installed, so that the
+# 'develop' phase doesn't faux-install the eggs in the root and
+# screw up the reset of the bulidout.
+recipe = zc.recipe.egg
+interpreter = w_persistent
+eggs = persistent
+
+[develop]
+recipe = zc.recipe.egg:develop
+setup = .
+executable = ${buildout:bin-directory}/w_persistent
+# Force the :develop recipe to prefer the excecutable defined in this section.
+python = develop
+
 [test]
 recipe = zc.recipe.testrunner
 eggs = BTrees [test]