config.gcc (s390-*-linux*): If 'enabled_targets' is 'all', build a bi-arch compiler defaulting to 31-bit.

2011-07-11  Arthur Loiret  <aloiret@debian.org>

        * config.gcc (s390-*-linux*): If 'enabled_targets' is 'all', build
        a bi-arch compiler defaulting to 31-bit. In this case:
        (tmake_file): Add s390/t-linux64.
        * doc/install.texi: Add s390-linux to the list of targets supporting
        --enable-targets=all.

From-SVN: r176146