[gfortran] Assorted matching fixes, fix No 1 from PR16404

[Paul Brook]

> 2004-07-13  Tobias Schlueter  <tobias.schlueter@physik.uni-muenchen.de>
>
> 	* PR fortran/16404
> 	(parts ported from g95)
> 	* parse.h (gfc_state_data): New field do_variable.
> 	(gfc_check_do_variable): Add prototype.
> 	* parse.c (push_state): Initialize field 'do_variable'.
> 	(gfc_check_do_variable): New function.
> 	(parse_do_block): Remember do iterator variable.
> 	(parse_file): Initialize field 'do_variable'.
> 	* match.c (gfc_match_assignment, gfc_match_do,
> 	gfc_match_allocate, gfc_match_nullify, gfc_match_deallocate):
> 	Add previously missing checks.
> 	(gfc_match_return): Reformat error message.
> 	* io.c (match_out_tag): New function.
> 	(match_open_element, match_close_element,
> 	match_file_element, match_dt_element): Call match_out_tag
> 	instead of match_vtag where appropriate.
> 	(match_io_iterator, match_io_element): Add missing check.
> 	(match_io): Reformat error message.
> 	(match_inquire_element): Call match_out_tag where appropriate.

Ok.

Paul