Don't always build coffgen.o

Removes a bunch of unused functions from libbfd when building ELF or
AOUT.  Split off the bits we need externally when not building a COFF
target into coff-bfd.c and coff-bfd.h.

bfd/
	* Makefile.am (BFD32_LIBS, BFD32_LIBS_CFILES): Remove dwarf2
	and coffgen.  Add coff-bfd.  Sort.
	(BFD32_BACKENDS, BFD32_BACKENDS_CFILES): Add coffgen and dwarf2.
	* bfd-in.h (bfd_coff_get_syment, bfd_coff_get_auxent): Delete.
	(struct coff_comdat_info, bfd_coff_get_comdat_section): Delete.
	* coffgen.c (coff_symbol_from): Move to coff-bfd.h as macro,
	without unused param.  Update uses.
	(bfd_coff_get_comdat_section): Move to coff-bfd.h as macro.
	(bfd_coff_get_syment, bfd_coff_get_auxent): Move to coff-bfd.c.
	* libcoff-in.h: #include "coff-bfd.h".
	(struct coff_section_tdata, coff_section_data): Move to coff-bfd.h.
	(coff_symbol_from): Delete.
	* coff-bfd.c: New file.
	* coff-bfd.h: New file.
	* coff-i386.c: Update coff_symbol_from occurrences.
	* coff-i960.c: Likewise.
	* coff-m68k.c: Likewise.
	* coff-sh.c: Likewise.
	* coff-x86_64.c: Likewise.
	* coffcode.h: Likewise.
	* pe-mips.c: Likewise.
	* configure.ac (elf): Add dwarf2.lo.
	(coffgen, coff, ecoff, xcoff): Define.  Use when mapping bfd
	target vectors to .o files.  Add dwarf2 for mach-o targets.
	Fix the sh target FIXME.
	* po/SRC-POTFILES.in: Regenerate.
	* Makefile.in: Regenerate.
	* configure: Regenerate.
	* bfd-in2.h: Regenerate.
	* libcoff.h: Regenerate.
binutils/
	* objdump.c: #include "coff-bfd.h".
ld/
	* ldmisc.c: #include "coff-bfd.h"

bfd/pe-mips.c

@@ -375,7 +375,7 @@ static reloc_howto_type howto_table[] =
       coffsym = (obj_symbols (abfd)				\
 	         + (cache_ptr->sym_ptr_ptr - symbols));		\
     else if (ptr)						\
-      coffsym = coff_symbol_from (abfd, ptr);			\
+      coffsym = coff_symbol_from (ptr);				\
     if (coffsym != NULL						\
 	&& coffsym->native->u.syment.n_scnum == 0)		\
       cache_ptr->addend = - coffsym->native->u.syment.n_value;	\