cpplib.h (struct cpp_reader): New field include_depth.
* 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.