re PR objc/21641 (cris-axis-elf, cris-axis-linux-gnu, mmix-knuth-mmixware, x86_64-unknown-linux-gnu broken libobjc/Object.m)

        PR objc/21641
        * objc-act.c (struct interface_tuple): Mark it up for GC.
        (interface_htab): It is really a struct interface_tuple.

From-SVN: r99922