bindir ?= $(PWD)
 
-all:
-       sed -e 's#@bindir@#$(bindir)#g' open_wrapper.sh.in > open_wrapper.sh \
-         && chmod +x open_wrapper.sh
+open_wrapper.sh: open_wrapper.sh.in
+       sed -e 's#@bindir@#$(bindir)#g' $< > $@ \
+         && chmod +x $@
 
 clean:
        rm -f open_wrapper.sh