* Makefile.am: Add support for elf32-arm.lo.

    * Makefile.am: Add support for elf32-arm.lo.
        * Makefile.in: Rebuild.
        * config.bfd (arm-*-elf):  Define targ_defvec and targ_selvecs.
        (thumb-*-elf): Define targ_defvec and targ_selvecs.
        * configure.in:  Handle bfd_elf32_littlearm_vec and bfd_elf32_bigarm_vec.
        * configure: Regenerate.
        * elf.c: (prep_headers):  Support arch_type of EM_ARM.
        * targets.c:  Support new targets bfd_elf32_bigarm_vec and
        bfd_target bfd_elf32_littlearm_vec.
        * elf32-arm.c:  New file.