* NEWS: dd bs= operands now silently override later ibs= and obs=,

as POSIX requires.
* src/dd.c (scanargs): Implement it.
* tests/dd/misc (outbytes): Test it.
* doc/coreutils.texi (dd invocation): Specify that bs=N
overrides later ibs and obs, undoing part of the
previous change.  (The behavior was wrong.)

tests/dd/misc

@@ -74,6 +74,9 @@ if dd oflag=nolinks if=$tmp_in of=$tmp_out 2> /dev/null; then
   dd oflag=nolinks < $tmp_in > $tmp_out 2>&1 || fail=1
 fi
 
+outbytes=`echo x | dd bs=3 ibs=10 obs=10 conv=sync 2>/dev/null | wc -c`
+test "$outbytes" -eq 3 || fail=1
+
 rm -f $tmp_in $tmp_in2 $tmp_sym $tmp_out
 
 exit $fail