* Removed sy_forward and replaced it with an undefined expression

	* Removed sy_forward and replaced it with an undefined expression
	as the value of a symbol.
	* struc-symbol.h (struct symbol): Removed sy_forward field.  Added
	sy_resolved and sy_resolving single bit fields.
	* symbols.c (symbol_new): Don't initialize sy_forward field.
	(resolve_symbol_value): New function to adjust symbol value by
	fragment address, using recursion to resolve forward symbols.
	* symbols.h: Added prototype for new function.
	* read.c (pseudo_set): Set symbolP->sy_value to an undefined
	expression rather than setting symbolP->sy_forward.
	* write.c (write_object_file): Use resolve_symbol_value on
	symbols, keeping the common case (the old behaviour) inline.
	* config/obj-aout.c (obj_aout_frob_symbol): Removed sy_forward
	handling (subsumed by write.c change).
	* config/obj-coff.c, config/obj-coffbfd.c (obj_coff_val): Set
	sy_value rather than sy_forward.
	* config/obj-coffbfd.c (obj_coff_endef, yank_symbols): Check
	expression segment rather than sy_forward.
	(yank_symbols): Use resolve_symbol_value.
	(crawl_symbols): Removed extra pass over symbols.
	* config/obj-aout.c, config/obj-bout.c, config/obj-coff.c,
	config/obj-vms.c (obj_crawl_symbol_chain): Removed extra pass over
	symbols which handled sy_forward; use resolve_symbol_value
	instead.
	* config/obj-coff.h, config/obj-coffbfd.h (obj_frob_forward_symbol):
	Define.
	* config/obj-elf.c (obj_elf_stab_generic): Check expression
	segment rather than sy_forward.
	* config/obj-vms.c (VMS_Check_For_Main): Don't initialize
	sy_forward; do initialize sy_resolved and sy_resolving.
	* config/tc-hppa.h (STAB_FIXUP): Use sy_value, not sy_forward.