The new availability directive introduced in  2d6097d027e0dd3debbabc702aa9c98d94ba32a3 (https://bugs.python.org/issue11233) breaks po files (sphinx-build -b gettext):

Here's the diff I'm getting on os.po from os.rst:

 msgid ""
-"Availability: Unix, Windows.  :func:`spawnlp`, :func:`spawnlpe`, :func:"
-"`spawnvp` and :func:`spawnvpe` are not available on Windows.  :func:"
-"`spawnle` and :func:`spawnve` are not thread-safe on Windows; we advise you "
-"to use the :mod:`subprocess` module instead."
+"Availability: Unix, Windows.  spawnlp(), spawnlpe(), spawnvp() and "
+"spawnvpe() are not available on Windows.  spawnle() and spawnve() are not "
+"thread-safe on Windows; we advise you to use the subprocess module instead."

The roles has been removed in the po files (but not in the original rst files), so it looks like the availability directive caused the drop of roles, but I still don't understand why.