[D] Move classification of symbols from the grammar to the lexer.

[D] Move classification of symbols from the grammar to the lexer.

This makes it so that alternating '.' and identifier tokens are resolved to
symbols as early as possible, which should all the addition of D properties -
such as EXP.sizeof and EXP.typeof - without the shift/reduce conflicts that
would occur in the current parsing strategy.

gdb/ChangeLog

	* d-exp.y (%union): Add voidval.
	(%token): Add UNKNOWN_NAME as a token to represent an unclassified
	name in the lexing stage.
	(PostfixExpression): Move symbol completion handling in grammar here
	from PrimaryExpression.
	(PrimaryExpression): Move routines to handle resolving identifier
	tokens in the grammar here from push_expression_name.
	(IdentifierExp): Remove the handling of alternating '.' and identifier
	tokens.
	(TypeExp): Allow TypeExp to be wrapped in parenthesis in the grammar.
	(BasicType): Remove C-style typename rules.
	(d_type_from_name, d_module_from_name, push_variable)
	(push_fieldnames, push_type_name, push_module_name)
	(push_expression_name): Remove.
	(lex_one_token): Rename from yylex.  Replace pstate with par_state.
	(token_and_value): New type.
	(token_fifo, popping, name_obstack): New globals.
	(classify_name): New function.
	(classify_inner_name): Likewise.
	(yylex): Likewise.
	(d_parse): Initialize token_fifo, popping and name_obstack.