Get rid of warnings which upset -Werror.

gas:
	* config/tc-arc.c (em_jumplink_or_jump_insn): Add extern
	declaration.
	(em_branch_or_jump_insn): Likewise.
	(arc_set_ext_seg): Comment out unneeded forward declaration, mark
	as static.
	(arc_handle_extinst): Comment out unneeded forward declaration,
	mark as static.  Move declaration after arc_extinst, and properly
	declare argument, which is not unused.
	(arc_extinst): Comment out unneeded forward declaration, mark
	as static.  Cast results of xstrdup to (unsigned char *).
	(arc_extoper): Comment out unneeded forward declaration, mark
	as static.
	(get_arc_exp_reloc_type): Likewise.
	(arc_insert_operand): Add dummy argument to as_warn ().
	(get_arc_exp_reloc_type): Mark first argument unused.
	(arc_add_ext_inst): Cast results of xstrdup to (unsigned char *).
	(arc_add_long_ext_inst): Likewise.
	(arc_generate_extinst32_operand_strings): Comment out unused
	suffixstr.
	(md_assemble): Cast loop test for insn_name_idx to unsigned
	int.  Cast args of strcmp and assignments to firstsuf to
	char *.  Add dummy arguments to as_warn and as_bad. Replace
	shadowed "s" by "s2".  Cast assignments to syn to unsigned
	char *.  Comment out unused sda_seen_p.  Replaced shadowed limm_p
	by limm2_p and limm by limm2.  Replaced shadowed operand by operand2.

opcodes:
	* arc-dis.c (print_insn_arc): Comment out unused function.
	* arc-opc-old.c (arc_get_branch_prediction): Add prototype
	declaration.
	(arc_reset_branch_prediction): Likewise.
	(em_jumplink_or_jump_insn): Likewise.
	(em_branch_or_jump_insn): Likewise.
	(brpredict): Comment out - unused.
	(arc_opcodes): Add parentheses to clarify expressions in pseudo
	menomnics or BRcc instruction.
	* arcompact-dis.c (CHECK_T): Add parentheses around use of "x".
	(ARCompact_decodeInstr): Remove all references to unused "bytes".
	Add extra parentheses to clarify logical expressions.
	(arcAnalyzeInstr): Remove all references to unused "bytes".

Conflicts:
	opcodes/ChangeLog.ARC
Fixed misplaced parenthesis and tidied up shadow variables.

gas:
	* config/tc-arc.c (md_assemble): No need to replace s by s2, limm
	by limm2 or limm_p by limm2_p. In each case we can just remove
	shadow declaration and reuse existing declaration.

opcodes:
	* arc-opc-old.c (arc_opcodes): Correct parentheses change for
	"brgt%.n %B,%u,%d".
        * arc-dis-old.c (write_comments_): Comment out unused function.
        (comment_prefix): Mark as ATTRIBUTE_UNUSED (used by above function).
        * arcompact-dis.c: Likewise.