[$] An alternative TTY layer

The Linux kernel is highly scalable but, while it runs nicely on theworld's largest computers, it is not an entirely comfortable fit on thesmallest. The difficulties involved in running Linux on machines with 1MBor less of memory have left an opening for other operating systems, such asZephyr, with lower memoryneeds. Some developers have not given up on scaling Linux to the smallestcomputers, but the approaches they have to take have always been a bit of ahard sell with the rest of the development community. Nicolas Pitre's minitty patch set is a case in point.