improve build script

build.sh

@@ -3,12 +3,18 @@
 
 set -e # exit asap
 
+# cleanup previous build
+if [ "$1" = "clean" ]; then
+  rm -rf ./dest ./void-packages
+  exit 0
+fi
+
 mkdir -p ./dest
 [ ! -d void-packages ] && git clone --depth 1 https://github.com/void-linux/void-packages.git
 ./void-packages/xbps-src binary-bootstrap
 
 for f in srcpkgs/*; do
-  cp ./"$f" ./void-packages/"$f" -ru
+  cp ./"$f" ./void-packages/"$f" -ruf
   ./void-packages/xbps-src pkg "$f"
   cp ./void-packages/hostdir/binpkgs/*.xbps ./dest/ -u
 done