$(Q) for grf in $(BIN_DIR)/orig*.obg; do sed 's/^OPENTTD.GRF = [0-9a-f]*$$/OPENTTD.GRF = '`md5sum $(BIN_DIR)/openttd.grf | sed 's@ .*@@'`'/' -i $$grf; done
$(Q) for grf in $(BIN_DIR)/orig*.obg; do sed 's/^OPENTTD.GRF = [0-9a-f]*$$/OPENTTD.GRF = '`$(MD5SUM) $(BIN_DIR)/openttd.grf | sed 's@ .*@@'`'/' $$grf > $$grf.tmp && mv $$grf.tmp $$grf; done