Port the bug fix for PR 19704 (Missing dynamic relocation against undefined weak...

Port the bug fix for PR 19704 (Missing dynamic relocation against undefined weak symbol) to the SPARC architecture.

       * elf32-sparc.c (elf_backend_fixup_symbol): New.
        * elf64-sparc.c (elf_backend_fixup_symbol): New.
        * elfxx-sparc.c (UNDEFINED_WEAK_RESOLVED_TO_ZERO): New.
        (_bfd_sparc_elf_link_hash_entry): Add has_got_reloc and
        has_non_got_reloc.
        (link_hash_newfunc): Initialize has_got_reloc and
	has_non_got_reloc.
        (_bfd_sparc_elf_size_dynamic_sections): Set interp to .interp
        section.
        (_bfd_sparc_elf_copy_indirect_symbol): Copy has_got_reloc and
        has_non_got_reloc.
        (_bfd_sparc_elf_check_relocs): Set has_got_reloc and
        has_non_got_reloc.
        (_bfd_sparc_elf_fixup_symbol): New function.
        (allocate_dynrelocs): Don't allocate space for dynamic
        relocations and discard relocations against resolved undefined
        weak symbols in executable.  Don't make resolved undefined weak
        symbols in executable dynamic.  Keep dynamic non-GOT/non-PLT
        relocation against undefined weak symbols in PIE.
        (_bfd_sparc_elf_relocate_section): Don't generate dynamic
        relocations against resolved undefined weak symbols in PIE
        (_bfd_sparc_elf_finish_dynamic_symbol): Keep PLT/GOT entries
        without ynamic PLT/GOT relocations for resolved undefined weak
        symbols.
        Don't generate dynamic relocation against resolved undefined
        weak symbol in executable.
        (pie_finish_undefweak_symbol): New function.
        (_bfd_sparc_elf_finish_dynamic_sections): Call
        pie_finish_undefweak_symbol on all symbols in PIE.
        * elfxx-sparc.h (_bfd_sparc_elf_link_hash_table): Add interp.
        (_bfd_sparc_elf_fixup_symbol): New function.