cccl: Respect silent flags.

Automake sets $V to tell the compiler whether to print verbose messages
as it compiles or not. Add support for this variable in cccl, allowing
more quiet build output on windows if the build is configured with
--silent or the developer runs make V=0.

Signed-off-by: Joe Stringer <joestringer@nicira.com>

build-aux/cccl

@@ -202,6 +202,8 @@ else
     opts=$linkopt
 fi
 
-echo "$prog $opts"
+if test x$V = x1 ; then
+    echo "$prog $opts"
+fi
 exec $prog $opts
 exit 0