* peXXigen.c: Updates for PE/COFF V8.0, and clarification

* peXXigen.c: Updates for PE/COFF V8.0, and clarification
  (dir_names): Added CLR Runtime Header to dir_names[].
  (_bfd_XX_print_private_bfd_data_common): Added EFI_ROM and XBOX subsystem names
  (_bfd_XXi_swap_aouthdr_in, _bfd_XXi_swap_aouthdr_out)
  (pe_print_idata, pe_print_edata)
  (_bfd_XX_bfd_copy_private_bfd_data_common)
  (_bfd_XXi_final_link_postscript): Use #DEFINEs for index into DataDirectory.
* pe.h: Added defines for IMAGE_SUBSYSTEM_EFI_ROM and IMAGE_SUBSYSTEM_XBOX.
* internal.h: Added defines for PE directory entry types.
  NB: in internal.h because IMAGE_NUMBEROF_DIRECTORY_ENTRYIES is in pe.h