Changed relocs to be based on subsegments (when BFD_ASSEMBLER).

	Changed relocs to be based on subsegments (when BFD_ASSEMBLER).
	* subsegs.h (struct frchain): If BFD_ASSEMBLER, added new fields
	fix_root and fix_tail.
	(segment_info_type): If BFD_ASSEMBLER, don't define fix_tail
	field.
	* write.c (fix_new_internal): If BFD_ASSEMBLER, set fix_rootP and
	fix_tailP based on frchain_now, not seg_info (now_seg).
	(chain_frchains_together_1): Chain the subsegment relocs together.
	* subsegs.c (subseg_change): Don't clear fix_tail field.
	(subseg_get): Likewise.
	* literal.c (add_to_literal_pool): Look through the relocs via
	frchain_now, not seginfo.

	* write.c (write_object_file): Simplified usage of obj_frob_symbol
	and tc_frob_symbol.  Always call both if the symbol is going to be
	output.

	* write.c (relax_segment): Use %ld rather than %d when printing
	fragP->fr_var, and cast it to long.