re PR libfortran/32456 (IO error message should show Unit/Filename)

re PR libfortran/32456 (IO error message should show Unit/Filename)

2007-06-24  Jerry DeLisle  <jvdelisle@gcc.gnu.org>

	PR libgfortran/32456
	* runtime/error.c (show_locus): Update to emit the unit number
	and file name involved with the error.  Use new function
	filename_from_unit.
	* libgfortran.h (filename_from_unit): Declare new function.
	* io/unit.c (init_units): Set the unit file name for stdin, stdout,
	and stderr for use later in error reporting.
	(filename_from_unit): Add this new function.

From-SVN: r125989