[PATCH v2 2/2] coff-go32: support extended relocations

[PATCH v2 2/2] coff-go32: support extended relocations

This patch extends the relocation and line number counters for
coff-go32 and coff-go32-exe to 32 bits.  As I understand it works the
same as for PE-COFF:

If the number of relocations in an object file exceeds 65534, the
NRELOC field is set to 65535 and the actual number of relocations is
stored in the VADDR field of the first relocation entry.

Executable files have no relocations, and thus the NRELOC field is
repurposed to extend NLNNO to 32-bits.

bfd	* coff-go32.c (COFF_GO32, IMAGE_SCN_LNK_NRELOC_OVFL)
	(coff_SWAP_scnhdr_in, coff_SWAP_scnhdr_out): Define.
	(_bfd_go32_swap_scnhdr_in, _bfd_go32_swap_scnhdr_out)
	(_bfd_go32_mkobject): New functions.
	* coff-stgo32.c (IMAGE_SCN_LNK_NRELOC_OVFL)
	(coff_SWAP_scnhdr_in, coff_SWAP_scnhdr_out): Define.
	(go32exe_mkobject): Call _bfd_go32_mkobject.
	* coffcode.h (COFF_WITH_EXTENDED_RELOC_COUNTER): Define.
	(coff_set_alignment_hook): Define function for COFF_GO32_EXE
	and COFF_GO32.
	(coff_write_relocs): Enable extended reloc counter code if
	COFF_WITH_EXTENDED_RELOC_COUNTER is defined.  Test for obj_go32.
	(coff_write_object_contents): Likewise.  Pad section headers
	for COFF_GO32 and COFF_GO32EXE.  Use bfd_coff_swap_scnhdr_out
	instead of coff_swap_scnhdr_out.
	* cofflink.c (_bfd_coff_final_link): Test also for obj_go32 to
	enable extended reloc counter.
	* coffswap.h: (coff_swap_scnhdr_in, coff_swap_scnhdr_out):
	Declare with ATTRIBUTE_UNUSED.
	* libcoff-in.h: (struct coff_tdata): New field go32.
	(obj_go32): Define.
	* libcoff.h: Regenerate.