* elf64-alpha.c (SKIP_HOWTO): New.

    * elf64-alpha.c (SKIP_HOWTO): New.
        (elf64_alpha_howto_table): Use it to remove dead ECOFF relocs.
        Fix sizes of 16-bit mem format relocs.
        (elf64_alpha_reloc_map): Update to match.
        (elf64_alpha_relax_with_lituse): Use GPREL16 as appropriate.
        (elf64_alpha_relax_without_lituse): Likewise.
        (elf64_alpha_check_relocs): Handle GPREL16.
        (elf64_alpha_relocate_section): Likewise.
        * reloc.c (BFD_RELOC_ALPHA_USER_*): Remove.
        (BFD_RELOC_ALPHA_GPREL_HI16, BFD_RELOC_ALPHA_GPREL_LO16): New.
        * bfd-in2.h, libbfd.h: Rebuild.