termcap in environment variables is wrong

[David Yost]

Ever try to run a screen command that uses termcap or
terminfo redirected to some other tty?

Environment variables are not the right place for
termcap and terminfo information.  This information
should be associated with the tty line.  Involving
the tty driver in this is too much to ask, but
vee have vays.

Here's how we might do it:
1.  Make a directory called /termcap/ which will
    contain files named 12-0, 12-1, etc.  (named for
    the major-minor of the ttys) which will contain
    a comment line like #/dev/ttyh1 followed by
    the termcap entry for the terminal.
2.  Write a setuid program that will let you write into
    those files if you have write permission on the
    associated device.
3.  Modify libtermcap.a to try to look for the termcap
    using this new approach, and if that fails, fall
    back to the old environment variable approach.

Similarly for terminfo.

The reason for the number-names rather than name-names
is that programs almost always work on ttys via a file
descriptor th