* ltcf-c.sh (aix4): Improve shared library configuration; require

        exporting symbols.
        * ltcf-cxx.sh (aix4): Define.
        * ltconfig (aix4): Define library and soname specs appropriate for
        AIX.  Define command to create export symbols list.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@37347 138bc75d-0d04-0410-961f-82ee72b054a4