Consolidation with CDI-PIO (develop)

Generally, this is !11 (merged) rebased onto the develop branch.

This is the first develop-based version accepted by the Buildbot of ICON: https://buildbot.dkrz.de/grid?branch=m300488/cdi-pio-2-integration

tests/deco2d_model.c

@@ -75,7 +75,7 @@ modelRun(struct model_config setup, MPI_Comm comm)
     Xt_redist redist4gather;
 #endif
   } * varDesc;
-  int gridID, taxisID, vlistID, streamID, tsID, tfID = 0;
+  int gridID, taxisID, vlistID, tsID, tfID = 0;
   enum
   {
     nmiss = 0
@@ -235,27 +235,15 @@ modelRun(struct model_config setup, MPI_Comm comm)
   taxisID = taxisCreate(TAXIS_ABSOLUTE);
   vlistDefTaxis(vlistID, taxisID);
 
-  composeFilename(&filename, fname_prefix, tfID, setup.suffix);
-  streamID = streamOpenWrite(filename, setup.filetype);
-  xassert(streamID >= 0);
-  streamDefVlist(streamID, vlistID);
-
-#ifdef USE_MPI
-  pioEndDef();
-#endif
-
   for (tfID = 0; tfID < ntfiles; tfID++)
     {
       for (size_t varIdx = 0; varIdx < nVars; ++varIdx) varDesc[varIdx].checksum_state = 0;
-      if (tfID > 0)
-        {
-          streamClose(streamID);
 
-          composeFilename(&filename, fname_prefix, tfID, setup.suffix);
-          streamID = streamOpenWrite(filename, setup.filetype);
-          xassert(streamID >= 0);
-          streamDefVlist(streamID, vlistID);
-        }
+      composeFilename(&filename, fname_prefix, tfID, setup.suffix);
+      int streamID = streamOpenWrite(filename, setup.filetype);
+      xassert(streamID >= 0);
+      streamDefVlist(streamID, vlistID);
+
       vdate = 19850101;
       vtime = 120000;
       current_time = cditime2time_t(vdate, vtime);
@@ -335,6 +323,7 @@ modelRun(struct model_config setup, MPI_Comm comm)
           pioWriteTimestep();
 #endif
         }
+      streamClose(streamID);
       if (rank == 0 && setup.compute_checksum)
         {
           FILE *tablefp;
@@ -360,11 +349,10 @@ modelRun(struct model_config setup, MPI_Comm comm)
           fclose(tablefp);
         }
     }
-  Free(varslice);
 #ifdef USE_MPI
   pioEndTimestepping();
 #endif
-  streamClose(streamID);
+  Free(varslice);
   vlistDestroy(vlistID);
   taxisDestroy(taxisID);
   for (size_t varIdx = 0; varIdx < nVars; varIdx++)