* t-h8300: Use TARGET_LIBGCC2_CFLAGS instead of LIBGCC2_CFLAGS.
        * t-mn10200: Ditto.
        * t-vxsparc: Ditto.
        * t-vxworks68: Ditto.
        * t-vxworks960: Ditto.
        * t-vx29k: Ditto.

From-SVN: r14984