Add some support for i960 MRI compatibility mode.

	Add some support for i960 MRI compatibility mode.
	* config/tc-i960.c (md_pseudo_table): Add endian.
	(get_args): Don't discard a space between alphanumeric characters.
	(get_cdisp): Change text_section to now_seg.
	(s_endian): New static function.
	* config/tc-i960.h (MRI_MODE_NEEDS_PSEUDO_DOT): Define.
	* expr.h (operatorT): Add O_logical_not, O_logical_and, and
	O_logical_or.
	* expr.c (operand): Treat '!' as logical not operator.  If
	TC_I960, in MRI mode permit `sizeof secname' and `startof
	secname'.
	(op_rank): Bump values by 2 to make room for && and ||.  Add
	entries for !, &&, and ||.
	(expr_begin): Only do MRI changes if TC_M68K.
	(operator): Recognize || and &&.
	(expr): Handle new operatorT values.
	* symbols.c (resolve_symbol_value): Handle new operatorT values.
	(print_expr_1): Likewise.
	* read.c (potable): Add debug, err, irep, irepc, print, purgem,
	and rep.
	(read_a_source_file): Handle MRI_MODE_NEEDS_PSEUDO_DOT.
	(mri_comment_field): Only handle weird comments if TC_M68K.
	(s_err): New function.
	(s_org): Only punt in MRI mode if TC_M68K.
	(s_mri_sect): Write TC_I960 version.
	(s_print, s_purgem): New functions.
	* read.h (s_err, s_print, s_purgem): Declare.
	* cond.c (s_ifeqs): Implement.
	(ignore_input): Handle MRI_MODE_NEEDS_PSEUDO_DOT.
	* macro.c (macro_strip_at): New static variable.
	(macro_init): Add strip_at parameter.
	(do_formals): If macro_strip_at, change NARG to $NARG.
	(define_macro): Skip a comma after the macro name.
	(get_apost_token): Skip character if macro_strip_at, even if
	macro_mri.
	(macro_expand_body): If macro_strip_at, don't recognize parameters
	in strings unless they are preceded by an '@'.  If macro_strip_at,
	pass '@' as strip character to sub_actual.  If macro_strip_at,
	strip '@' characters.
	(macro_expand): If macro_strip_at, change NARG to $NARG.
	(delete_macro): New function.
	(expand_irp): Skip leading and trailing '"' characters if irpc.
	* macro.h (macro_init): Mention new strip_at parameter.
	(delete_macro): Declare.
	* as.c (main): If TC_I960, pass flag_mri to macro_init as
	strip_at; otherwise, pass 0.
	* gasp.c (process_pseudo_op): Pass 0 to macro_init as strip_at.
	(main): Likewise.
	* doc/as.texinfo: Document i960 MRI mode.

	* as.c (show_usage): Mention --defsym.