* configure.in (enable-shared): New.
        * Makefile.in (LIBGCC_DEPS): Depend on EXTRA_PARTS as well.
        (libgcc.mk): Pass SHLIB_LINK, SHLIB_LIBS, SHLIB_MULTILIB to mklibgcc.
        * mklibgcc.in: Use them to link shared a libgcc.
        * config/t-linux (SHLIB_LINK, SHLIB_LIBS): New.
        * config/alpha/t-ieee (SHLIB_MULTILIB): New.
        * config/mips/t-iris6 (SHLIB_LINK, SHLIB_LIBS): New.
        * config/sparc/t-sol2 (SHLIB_LINK, SHLIB_LIBS): New.

        * configure.in (alpha-osf*): Use t-osf and x-osf.
        * config/alpha/t-osf: New file.
        * config/alpha/t-osf4: New file.
        * config/alpha/x-osf: New file.
        * config/alpha/x-alpha: Remove file.

From-SVN: r36715