testsuite ChangeLog:

2014-09-17  Janne Blomqvist  <jb@gcc.gnu.org>

	PR libfortran/62768
	* gfortran.dg/filename_null.f90: New test.

libgfortran ChangeLog:

2014-09-17  Janne Blomqvist  <jb@gcc.gnu.org>

	PR libfortran/62768
	* io/io.h (gfc_unit): Store C string for the filename.
	* io/close.c (st_close): Use gfc_unit.filename.
	* io/inquire.c (inquire_via_unit): Likewise.
	* io/open.c (new_unit): Likewise.
	(already_open): Likewise, unlink file before freeing filename.
	* io/unit.c (init_units): Likewise.
	(close_unit_1): Likewise.
	(filename_from_unit): Likewise.
	* io/unix.c (compare_file_filename): Likewise.
	(find_file0): Likewise.
	(delete_file): Likewise.

From-SVN: r215307