* check.c (gfc_check_ttynam_sub, gfc_check_isatty): Add check
	functions for new intrinsics TTYNAM and ISATTY.
	* intrinsic.c (add_functions, add_subroutines): Add new
	intrinsics.
	* intrinsic.h: Add prototypes for new check and resolve
	functions.
	* iresolve.c (gfc_resolve_isatty, gfc_resolve_ttynam_sub): New
	resolve functions for intrinsics TTYNAM and ISATTY.
	* gfortran.h (gfc_generic_isym_id): Add symbol for ISATTY.
	* trans-intrinsic.c: Add case for GFC_ISYM_ISATTY.
	* Makefile.am: Add file intrinsics/tty.c to Makefile process.
	* Makefile.in: Regenerate.
	* io/io.h: Prototypes for new functions stream_isatty and
	stream_ttyname.
	* io/unix (stream_isatty, stream_ttyname): New functions to call
	isatty() and ttyname() on a given unit.
	* intrinsics/tty.c: New file to implement g77 intrinsics TTYNAM
	and ISATTY.

From-SVN: r102915