Bug in C library

[utzoo!utcsrgv!drg]

The undocumented rin() routine in /lib/libc.a calls the non-existent
routine isdigit(), generating a very confusing loader message.

Rin() (read integer) is left over from v6.  It is obviously not used
by anyone, or they would have fixed this bug.  I recommend removing
it from the library, and forcing people to use scanf() instead.

		-- Dave Galloway, CSRG, University of Toronto