* i386nbsd-nat.c: Delete file. Move fetch_core_registers and

* i386nbsd-nat.c: Delete file.  Move fetch_core_registers and
fetch_elfcore_registers to...
* i386nbsd-tdep.c: ...here.
(i386nbsd_use_struct_convention): Rename to...
(i386nbsd_aout_use_struct_convention): ...this.
(i386nbsd_supply_reg): New function.
(i386nbsd_fill_reg): New function.
(fetch_core_registers): Use i386nbsd_supply_reg.
(fetch_elfcore_registers): Likewise.
(_initialize_i386nbsd_tdep): New function.
* config/i386/nbsd.mh (NATDEPFILES): Remove i386nbsd-nat.o.
* config/i386/nbsdelf.mh (NATDEPFILES): Likewise.
* config/i386/nbsdelf.mt (TDEPFILES): Add i386nbsd-tdep.o.
* config/i386/tm-nbsd.h (i386nbsd_use_struct_convention): Rename to...
(i386nbsd_aout_use_struct_convention): ...this.