PR 1150

PR 1150
* readelf.c (get_mips_symbol_other): New function.
  (get_symbol_other): New function.
  (process_symbol_table): Call get_symbol_other() to get a description of the
    st_other field if it contains more information than just the visibility.
* elfxx-mips.c (mips_elf_calculate_relocation): Ignore an undefined symbol if
    it is optional.
  (_bfd_mips_elf_merge_symbol_attribute): Make sure that the optional flag is
    merged as well as the visibility.
* elfxx-mips.h (_bfd_mips_elf_merge_symbol_attribute): Prototype.
  (elf_backend_merge_symbol_attribute): Define.
* mips.h (STO_OPTIONAL): Define.
  (ELF_MIPS_IS_OPTIONAL): Define.