ls, declaring lib functions

[utzoo!decvax!ucbvax!mbm at mit-cipg]

From: mbm at mit-cipg at mit-mc

Berkeley's ls does not report the year of old files on the pdp11,
because it does not declare time() to be long, and always thinks
the current year is 1969. 

Strictly, time should probably be declared time_t.

This is a perennial problem in C, especially in regards to portability
to other machines and systems.  I think we should extend the idea of
<math.h> and <stdio.h> to an include file for all the C library routines
(system call interfaces and others), say <libc.h>, so that non-int
functions would get properly declared automagically by including this file.

[My apologies to those on more than one of these lists.]
--mike