stream choice header.

dune/fem-dg/misc/Makefile.am

 miscdir = $(includedir)/dune/fem-dg/misc
-misc_HEADERS = runfile.hh cons2prim.hh
+misc_HEADERS = runfile.hh cons2prim.hh streams.hh
 
 include $(top_srcdir)/am/global-rules

dune/fem-dg/misc/streams.hh

+#ifndef DUNE_FEM_DG_STREAMS_HH
+#define DUNE_FEM_DG_STREAMS_HH
+
+#if HAVE_SIONLIB && USE_SIONLIB
+#warning "using SIONlib streams for output"
+
+#include <dune/fem/io/streams/sionlibstreams.hh>
+namespace Dune {
+
+  struct PersistenceManagerTraits
+  {
+    typedef Fem :: SIONlibOutStream  BackupStreamType ;
+    typedef Fem :: SIONlibInStream   RestoreStreamType ;
+    static const bool singleBackupRestoreFile = true ;
+  };
+
+#define FEM_PERSISTENCEMANAGERSTREAMTRAITS  PersistenceManagerTraits
+}
+#endif // #if HAVE_SIONLIB && USE_SIONLIB
+
+#endif // #ifndef DUNE_FEM_DG_STREAMS_HH