diff -u -r ../optipng-0.7.4/configure ./configure
--- ../optipng-0.7.4/configure	2012-08-25 02:12:00.000000000 +0200
+++ ./configure	2014-03-19 00:01:50.000000000 +0100
@@ -130,7 +130,6 @@
     * )
         echo "error: unknown option: $arg"
         echo "Type \"$0 -help\" for help"
-        exit 64  # EX_USAGE
         ;;
     esac
 done