Stop using bfd_usrdata in libbfd.
* coff-stgo32.c (bfd_coff_go32stub): Remove.
(stub_bytes, comment): Replace STUBSIZE by GO32_STUBSIZE.
(adjust_filehdr_in_post): Declare the abfd parameter as unused.
Replace STUBSIZE by GO32_STUBSIZE. Save now the stub in
filehdr_dst->u.go32.stub. New comment with the reason.
(adjust_filehdr_out_pre): Replace STUBSIZE by GO32_STUBSIZE.
Substitute the removed macro bfd_coff_go32stub.
(adjust_filehdr_out_post, adjust_scnhdr_in_post, adjust_scnhdr_out_pre)
(adjust_scnhdr_out_post, adjust_aux_in_post, adjust_aux_out_pre)
(adjust_aux_out_post): Replace STUBSIZE by GO32_STUBSIZE.
(create_go32_stub, go32_stubbed_coff_bfd_copy_private_bfd_data):
Replace STUBSIZE by GO32_STUBSIZE. Substitute the removed macro
bfd_coff_go32stub.
* coffcode.h (coff_mkobject_hook): Initialize coff->go32stub.
* libcoff-in.h (coff_data_type): New field go32stub.
* libcoff.h: Regenerated.
include/coff/
Stop using bfd_usrdata in libbfd.
* go32exe.h (struct external_filehdr_go32_exe <stub>, FILHSZ): Replace
STUBSIZE by GO32_STUBSIZE.
(STUBSIZE): Move the definition ...
* internal.h (GO32_STUBSIZE): ... here and rename it.
(struct internal_filehdr <go32stub>, F_GO32STUB): New.
