I tried to update to the tip of bzr repo today but got this upon waf configure:

pybindgen                                                                          : ok 
Traceback (most recent call last):
  File "<string>", line 1, in <module>
ImportError: No module named version
Traceback (most recent call last):
  File "/a/users/tomh/bake/source/ns-3-dev/.waf-1.7.13-5a064c2686fe54de4e11018d22148cfc/waflib/Scripting.py", line 97, in waf_entry_point
    run_commands()
  File "/a/users/tomh/bake/source/ns-3-dev/.waf-1.7.13-5a064c2686fe54de4e11018d22148cfc/waflib/Scripting.py", line 153, in run_commands
    ctx=run_command(cmd_name)
  File "/a/users/tomh/bake/source/ns-3-dev/.waf-1.7.13-5a064c2686fe54de4e11018d22148cfc/waflib/Scripting.py", line 146, in run_command
    ctx.execute()
  File "/a/users/tomh/bake/source/ns-3-dev/.waf-1.7.13-5a064c2686fe54de4e11018d22148cfc/waflib/Configure.py", line 128, in execute
    super(ConfigurationContext,self).execute()
  File "/a/users/tomh/bake/source/ns-3-dev/.waf-1.7.13-5a064c2686fe54de4e11018d22148cfc/waflib/Context.py", line 87, in execute
    self.recurse([os.path.dirname(g_module.root_path)])
  File "/a/users/tomh/bake/source/ns-3-dev/.waf-1.7.13-5a064c2686fe54de4e11018d22148cfc/waflib/Context.py", line 128, in recurse
    user_function(self)
  File "/a/users/tomh/bake/source/ns-3-dev/wscript", line 376, in configure
    conf.recurse('bindings/python')
  File "/a/users/tomh/bake/source/ns-3-dev/.waf-1.7.13-5a064c2686fe54de4e11018d22148cfc/waflib/Context.py", line 128, in recurse
    user_function(self)
  File "/a/users/tomh/bake/source/ns-3-dev/bindings/python/wscript", line 171, in configure
    pybindgen_version = tuple([int(x) for x in pybindgen_version_str.split('.')])
ValueError: invalid literal for int() with base 10: ''