* lto-opts.c (input_data_block): Move to lto-streamer-in.c.
	* lto-streamer-in.c (input_string_internal): Add clarifying
	comments.
	(lto_input_data_block): Move from lto-opts.c.  Make extern.
	Update all users.
	(lto_input_string): Rename from input_string.  Make extern.
	Update all users.
	* lto-streamer-out.c (lto_output_string_with_length): Rename from
	output_string_with_length.
	Output 0 to indicate a non-NULL string.  Update all callers to
	not emit 0.
	(lto_output_string): Rename from output_string.  Make extern.
	Update all users.
	(lto_output_decl_state_streams): Make extern.
	(lto_output_decl_state_refs): Make extern.
	* lto-streamer.h (lto_input_string): Declare.
	(lto_input_data_block): Declare.
	(lto_output_string): Declare.
	(lto_output_string_with_length): Declare.
	(lto_output_decl_state_streams): Declare.
	(lto_output_decl_state_refs): Declare.

From-SVN: r171387