gccgo: 	fixes to ast-dump, refactoring of export and ast-dump
        to implement a common interface for writing basic
        type literals and added flags for optimization.

	* lang.opt: Add fgo-optimize-.
	* go-lang.c (go_langhook_handle_option): Handle OPT_fgo_optimize.
	* go-c.h (go_enable_optimize): Declare.
	* Make-lang.in (GO_OBJS): Add go/go-optimize.o.
	(GO_EXPORT_H): Define.
	(GO_IMPORT_H): Add $(GO_EXPORT_H).
	(GO_AST_DUMP_H): Define.
	(go/ast-dump.o, go/statements.o): Use GO_AST_DUMP_H.
	(go/export.o, go/gogo.o, go/import.o): Use GO_EXPORT_H.
	(go/types.o): Likewise.
	(go/expressions.o): Use GO_AST_DUMP_H and GO_EXPORT_H.
	(go/go-optimize.o): New target.

From-SVN: r178046