[coreutils] ignore-value.h considered harmful

[Paul Eggert]

Re that recent change to sort.c to insert a call to ignore_value.

This ignore_value business is ugly, and
runs against the spirit of the GNU coding standards:

  "Don't make the program ugly to placate lint.
   Please don't insert any casts to void."

  <http://www.gnu.org/prep/standards/html_node/Syntactic-Conventions.html>

How about if we suppress those GCC warnings instead, using
-Wno-unused-result or whatever-it-is?  The cost of this
particular warning seems to be greater than its benefits.