bug#7451: Better name for $(AM_V_at)?

[Stefano Lattarini]

From the automake manual, section on the "silent-rules" option:

 ``You can use the predefined variable $(AM_V_GEN) as a prefix to
   commands that should output a status line in silent mode, and
   $(AM_V_at) as a prefix to commands that should not output
   anything in silent mode.  When output is to be verbose, both
   of these variables will expand to the empty string.''

Could we find a better name than $(AM_V_at)?

 - $(AM_V_SILENT) is nice, but also a bit too long.  I wouldn't mind,
   but some people dislike long names for often-used variables.

 - $(SILENT) is shorter, but too much invasive of the user namespace.
   I'd strongly advise against it.

 - Other suggestions?

If we find such a better name, we should then deprecate $(AM_V_at),
but *not* remove it: it should be kept for backward-compatibility
(probably for quite a long time).

See also this older thread
 <http://lists.gnu.org/archive/html/bug-automake/2010-04/msg00001.html>

Regards,
  Stefano