* cppexp.c: Don't include cpphash.h.
	(parse_charconst, cpp_lex): Use cpp_defined.
	(cpp_lex): Use get_directive_token throughout.  Remove
	unnecessary cases from switch.  Move assertion-handling code
	down to OTHER case.
	(cpp_parse_expr): If we see '+' or '-', check the context to
	determine if they are unary or binary operators.  Streamline
	the jumps a bit.  Do not call skip_rest_of_line.

	* cpplib.c: Make skip_rest_of_line and cpp_skip_hspace
	static.  Export get_directive_token.  Update commentary.
	(cpp_defined): New function.
	(do_define): Remove reference to T_PCSTRING.  Call
	free_definition to release memory for old definition, when
	redefining a macro.
	(eval_if_expression): Set only_seen_white to 0 before calling
	cpp_parse_expr.  Call skip_rest_of_line after it returns.
	(cpp_read_check_assertion): Don't preserve a pointer into the
	token buffer across a call to cpp_get_token.

	* Makefile.in (cppexp.o): Don't depend on cpphash.h.
	* cppfiles.c (redundant_include_p): Use cpp_defined.
	* cpphash.c (free_definition): New function.
	(delete_macro): Use it.  Update commentary.
	* cpphash.h: Typedef HASHNODE here.  Prototype cpp_lookup and
	free_definition.
	* cpplib.h: Don't typedef HASHNODE here. Delete T_PCSTRING
	from enum node_type.  Prototype cpp_defined and get_directive_token.
	Don't prototype cpp_lookup, skip_rest_of_line, or cpp_skip_hspace.

	* fix-header.c (check_macro_names): Use cpp_defined.
	(read_scan_file): Set inhibit_warnings and inhibit_errors in
	the options structure.

From-SVN: r31908