improve build script

build.sh

@@ -4,8 +4,12 @@ cp -f config.mk Makefile patches.h st-flexipatch/
 flexipatch-finalizer/flexipatch-finalizer.sh -r -d st-flexipatch -o st-final
 git -C st-flexipatch reset --hard HEAD && git -C st-flexipatch clean -fd
 for patch in patches/*.diff; do
-	patch -d st-final <"$patch"
+    patch -d st-final <"$patch"
 done
 cp -f config.h st-final/
 cd st-final || exit 1
-make
+if [ "$1" = "-i" ]; then
+    sudo make install
+else
+    make
+fi