* cpplib.h (struct cpp_reader): New field include_depth.
	(struct cpp_printer): Rename last_bsd to last_id.
	* cppfiles.c (read_include_file): Bump include_depth.
	* cpplex.c (cpp_pop_buffer): Decrement include_depth.
	(output_line_command): Output correct #line if a header
	is including itself and is not protected against multiple inclusion.
	Use include_depth instead of buffer_stack_depth, last_id instead of
	last_bsd.
	* cppinit.c (cpp_start_read): Initialize last_id instead of
	last_bsd.

From-SVN: r34831