* syntax.c: Integer cleanups.

* syntax.c: Integer cleanups.

(SYNTAX_FLAGS_COMMENT_STYLEC): Return a boolean, not 0-or-2.
All uses that need 0-or-2 changed to:
(SYNTAX_FLAGS_COMMENT_STYLEC2): New macro, with the same semantics
as the old SYNTAX_FLAGS_COMMENT_STYLEC.
(struct lisp_parse_state, syntax_prefix_flag_p, update_syntax_table)
(char_quoted, prev_char_comend_first, back_comment)
(Finternal_describe_syntax_value, skip_chars, skip_syntaxes)
(in_classes, forw_comment, scan_lists, scan_sexps_forward):
Use bool for boolean.
(update_syntax_table, skip_chars, skip_syntaxes):
Prefer int to unsigned when either will do.
(back_comment): Return boolean success flag, like forw_comment,
instead of positive-or-minus-1 (which might have overflowed int anyway).
Don't stuff ptrdiff_t into int.
(syntax_spec_code, syntax_code_spec): Now const.
(Fmatching_paren, scan_lists, scan_sexps_forward):
Use enum syntaxcode for syntax code.
(Fmatching_paren): Check that arg is a character, not just an integer.
(Fstring_to_syntax): Don't assume 0377 fits in enum syntaxcode.
(Finternal_describe_syntax_value): Omit no-longer-needed
comparison to 0.
(skip_chars): Use char, not unsigned char, when the distinction
doesn't matter.
(forw_comment, scan_lists): Prefer A |= B to A = A || B when B's cheap.
* bytecode.c (exec_byte_code):
* syntax.c (syntax_spec_code, Fchar_syntax)
(Finternal_describe_syntax_value, skip_chars, skip_syntaxes)
(init_syntax_once):
* syntax.h (SYNTAX_WITH_FLAGS):
Omit unnecessary casts.