diff --git a/v2/tools/mpi.jam b/v2/tools/mpi.jam
index 12c2993e9..38012474e 100644
--- a/v2/tools/mpi.jam
+++ b/v2/tools/mpi.jam
@@ -218,7 +218,7 @@ rule cmdline_to_features ( cmdline : unknown-features ? )
     if $(otherflags) {
        for unknown in $(unknown-features)
        {
-         result += "$(unknown)$(otherflags)" ;
+         result += "$(unknown)$(otherflags:J= )" ;
        }
     }