Use ionice for better host responsiveness

openwrtbuilder

@@ -676,7 +676,7 @@ fromSource() {
     execute make "${make_opts[@]}" "-j1" defconfig download clean
 
     # Make image
-    if ! execute make "${make_opts[@]}" "-j$(($(nproc)+1))" world; then
+    if ! execute ionice -c 3 chrt --idle 0 nice -n19 make "${make_opts[@]}" "-j$(($(nproc)+1))" world; then
         echo "Error: make failed, retrying using slow mode"
         if ! execute make V=s -j1 dirclean world; then
             echo "Error: slow make failed"