diff --git a/setup.cfg b/setup.cfg
index 41e20daff..a9ccb4beb 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -37,7 +37,7 @@ find_links=misc/dependencies tahoe-deps ../tahoe-deps
 # (See http://tahoe-lafs.org/trac/tahoe-lafs/ticket/142 .)
 
 [aliases]
-build = darcsver --count-all-patches develop --prefix=support make_executable build
+build = darcsver --count-all-patches develop --multi-version --prefix=support make_executable build
 test = darcsver --count-all-patches develop --prefix=support make_executable build trial
 sdist = darcsver --count-all-patches sdist
 install = darcsver --count-all-patches install
diff --git a/src/allmydata/scripts/keygen.py b/src/allmydata/scripts/keygen.py
index f96b3a769..c1d09786a 100644
--- a/src/allmydata/scripts/keygen.py
+++ b/src/allmydata/scripts/keygen.py
@@ -14,6 +14,9 @@ class CreateKeyGeneratorOptions(BasedirMixin, BaseOptions):
 keygen_tac = """
 # -*- python -*-
 
+import pkg_resources
+pkg_resources.require('allmydata-tahoe')
+
 from allmydata import key_generator
 from twisted.application import service