doc: update for ISO/IEC 80000-13

doc: update for ISO/IEC 80000-13

* doc/coreutils.texi (Block size): IEC 60027-2 has been superseded
by ISO/IEC 80000-13, so prefer the newer standard but also mention
the old.  The new standard specifies Zi and Yi, so they are no
longer GNU extensions.  Fix stale URL to BIPM.

2011-11-14  Paul Eggert  <eggert@cs.ucla.edu>

id: handle (uid_t) -1 more portably
* src/id.c (GETID_MAY_FAIL): Remove.
(main): Check for negative return values, not for -1.
The old code was incorrect if uid_t was narrower than int,
regardless of whether we were on a GNU or a POSIX platform.
The new code is simpler and doesn't need GETID_MAY_FAIL.
(print_full_info): Remove unnecessary cast to -1.