Some older versions of configure (including the one in GMP 4.3.2)
interpret the $ECHO environment variable as the `echo' utility to
use. CT-NG sets the variable to `:' and exports it if V=0 or V=1
is supplied, breaking the samples using such configure. This currently
includes bfin-unknown-linux-uclibc and powerpc-unknown-linux-uclibc.
Also, correct the description of the V= variable - V=0 is *not* the
default; in fact, default does not correspond to any of the V=[012]
values.
Signed-off-by: Alexey Neyman <stilor@att.net>