* archures.c (bfd_mach_m68*): Add definitions for various m68k
variants.
(bfd_default_scan): Remove m68k special cases.
* bfd-in2.h: Rebuild.
* mipsbsd.c (MY(write_object_contents)): Use bfd_mach_m680*
instead of plain numbers.
* sparclynx.c (NAME(lynx,set_arch_mach)): Likewise.
* cpu-m68k.c (arch_info_struct): Likewise. Add entry for
m68k:68000.
(bfd_m68k_arch): Set mach field to zero to signal no explicit
selection, change printable_name to just "m68k" and make that the
default instead of m68k:68020.
