diff --git a/sphinx/__init__.py b/sphinx/__init__.py
index c091a6776..cc0a66031 100644
--- a/sphinx/__init__.py
+++ b/sphinx/__init__.py
@@ -15,8 +15,8 @@
 import sys
 from os import path
 
-__version__  = '1.2b1'
-__released__ = '1.2b1'  # used when Sphinx builds its own docs
+__version__  = '1.2b1-xgen1-'
+__released__ = '1.2b1-xgen1-'  # used when Sphinx builds its own docs
 
 package_dir = path.abspath(path.dirname(__file__))
 
diff --git a/sphinx/builders/__init__.py b/sphinx/builders/__init__.py
index 3ff5a161c..026cbdb77 100644
--- a/sphinx/builders/__init__.py
+++ b/sphinx/builders/__init__.py
@@ -354,6 +354,8 @@ class Builder(object):
         # for the rest, determine how many documents to write in one go
         ndocs = len(docnames)
         chunksize = min(ndocs // nproc, 10)
+        if chunksize == 0:
+            chunksize = 1
         nchunks, rest = divmod(ndocs, chunksize)
         if rest:
             nchunks += 1