* sysdeps/unix/sysv/linux/Makefile [$(subdir)=termios] (headers):

* sysdeps/unix/sysv/linux/Makefile [$(subdir)=termios] (headers):

	Append termio.h.

	* Makefile ($(includedir)/stubs.h): Print a msg if we do nothing.

	* misc/sgtty.h: Add forward decl of struct sgttyb in case it is never
	defined.

	* sysdeps/unix/sysv/linux/termio.h: New file.
	* sysdeps/unix/sysv/linux/Dist: Add it.

	* sysdeps/unix/sysv/linux/ioctl-types.h: New file, wrapper around
	kernel header <asm/termios.h>.

	* misc/Makefile (headers): Add ioctl-types.h.
	* sysdeps/generic/ioctl-types.h: New file.
	* misc/sys/ioctl.h: Include <ioctl-types.h>.
	(struct tchars, struct ltchars, struct sgttyb, struct winsize,
	struct ttysize): Types moved there.