Parallel make failed for me:

  /usr/bin/xsltproc --output man/nm-settings-keyfile.xml ...
    ... man/nm-settings-keyfile.xsl libnm/nm-settings-keyfile-docs.xml
  man/nm-settings-keyfile.xsl:4: warning: failed to load external entity "man/common.ent"
  %entities;
            ^
  man/nm-settings-keyfile.xsl:26: parser error : Entity 'NM_VERSION' not defined
          <refmiscinfo class="version">&NM_VERSION;</refmiscinfo>
                                                   ^
  cannot parse man/nm-settings-keyfile.xsl
  make[2]: *** [Makefile:18130: man/nm-settings-keyfile.xml] Error 4