re PR libfortran/23272 ([mingw32] inquire via filename fails)

re PR libfortran/23272 ([mingw32] inquire via filename fails)

	PR libfortran/23272
	* acinclude.m4 (LIBGFOR_CHECK_WORKING_STAT): New check.
	* configure.ac: Use LIBGFOR_CHECK_WORKING_STAT.
	* Makefile.in: Regenerate.
	* aclocal.m4: Regenerate.
	* config.h.in: Regenerate.
	* configure: Regenerate.
	* io/unix.c (compare_file_filename): Add fallback case for
	systems without working stat.
	* io/open.c (already_open): Correct call to
	compare_file_filename.
	* io/io.h: Correct proto for compare_file_filename.

From-SVN: r105824