diff -u -r ../RHash-1.3.6/configure ./configure
--- ../RHash-1.3.6/configure	2018-03-14 02:42:17.000000000 +0100
+++ ./configure	2018-04-22 21:56:37.741263688 +0200
@@ -193,8 +193,7 @@
     BUILD_EXTRA_LDFLAGS=$(get_opt_value $OPT)
     ;;
   *)
-      echo "unknown option $OPT"
-      exit 1
+      echo "WARNING: unknown option $OPT"
       ;;
   esac
   shift