* Remove undef NULL, EOF, getchar, putchar
* Rename putchar, getchar, _putchar, _getchar to putch, getch, _putch,
_getch to avoid conflict with libc functions.
* Rename UP() to UP1() (for UP 1 line) to avoid conflict with UP
definition in termcap.h. Rename DN1 LF1 RT1 for consistency.
* Add termcap.h for prototypes for tputs and friends.
* Add libterminfo references to Makefile
* Add return value to _putch() to make it work as tputs expects.
* Make putch() call _putch()
* Remove UNIX ifdefs and all code in the !UNIX branches.