Show whether generated setup.h files changed or not

Don't output "ok" for all files when running update-setup-h, this was
not very informative and possibly misleading. Only show "ok" for the
actually updated files and "unchanged" otherwise.

build/update-setup-h

@@ -65,7 +65,12 @@ update_single_setup_h()
     tmp=$i.$$.tmp
     sed -e "/^\/\* --- start $section options --- \*\/\$/q" $1 > $tmp &&
     cat_common_options_for $setup_inc $1 >> $tmp &&
-    sed -n -e "/^\/\* --- end $section options --- \*\/\$/,\$p" $1 >> $tmp &&
+    sed -n -e "/^\/\* --- end $section options --- \*\/\$/,\$p" $1 >> $tmp
+
+    if cmp -s $1 $tmp; then
+        rm $tmp
+        msg " unchanged"
+    else
         mv $tmp $1
 
         if [ $? -ne 0 ]; then
@@ -75,6 +80,7 @@ update_single_setup_h()
         else
             msg " ok"
         fi
+    fi
 }
 
 # wrapper for update_single_setup_h which only updates the common options