title: Meson: ERROR: add_project_arguments keyword argument "language" unknown languages: python
body: <p>I want to install <a href="https://github.com/infirit/caja-admin" rel="nofollow noreferrer">this</a> project with meson. It worked flawlessly all the time but since about three weeks it fails with (I think because of the latest 0.59 release, could not find any changes that could have caused this):</p>
  <pre class="lang-sh prettyprint-override"><code>po/meson.build:3:0: ERROR: add_project_arguments keyword argument &quot;language&quot; unknown languages: python
  </code></pre>
  <p>This is the content of the meson.build in the po directory:</p>
  <pre class="lang-py prettyprint-override"><code>i18n = import('i18n')
  # define GETTEXT_PACKAGE
  add_project_arguments('-DGETTEXT_PACKAGE=&quot;caja-admin&quot;', language:'python')
  i18n.gettext(meson.project_name(),
      args: '--directory=' + meson.source_root()
  )
  </code></pre>