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

src/model.c

@@ -259,14 +259,14 @@ enum
   MODEL_PACK_INT_INSTID,
   MODEL_PACK_INT_MODELGRIBID,
   MODEL_PACK_INT_NAMELEN,
-  model_nints,
+  modelNints,
 };
 
 static int
 modelGetSizeP(void *modelptr, void *context)
 {
   model_t *p = (model_t *) modelptr;
-  size_t txsize = (size_t) serializeGetSize(model_nints, CDI_DATATYPE_INT, context)
+  size_t txsize = (size_t) serializeGetSize(modelNints, CDI_DATATYPE_INT, context)
                   + (size_t) serializeGetSize(p->name ? (int) strlen(p->name) : 0, CDI_DATATYPE_TXT, context);
   xassert(txsize <= INT_MAX);
   return (int) txsize;
@@ -276,12 +276,12 @@ static void
 modelPackP(void *modelptr, void *buf, int size, int *position, void *context)
 {
   model_t *p = (model_t *) modelptr;
-  int tempbuf[model_nints];
+  int tempbuf[modelNints];
   tempbuf[MODEL_PACK_INT_SELF] = p->self;
   tempbuf[MODEL_PACK_INT_INSTID] = p->instID;
   tempbuf[MODEL_PACK_INT_MODELGRIBID] = p->modelgribID;
   tempbuf[MODEL_PACK_INT_NAMELEN] = p->name ? (int) strlen(p->name) : 0;
-  serializePack(tempbuf, model_nints, CDI_DATATYPE_INT, buf, size, position, context);
+  serializePack(tempbuf, modelNints, CDI_DATATYPE_INT, buf, size, position, context);
   if (p->name) serializePack(p->name, tempbuf[MODEL_PACK_INT_NAMELEN], CDI_DATATYPE_TXT, buf, size, position, context);
 }
 
@@ -289,9 +289,9 @@ int
 modelUnpack(void *buf, int size, int *position, int originNamespace, void *context, int force_id)
 {
 #define adaptKey(key) (namespaceAdaptKey((key), originNamespace))
-  int tempbuf[model_nints];
+  int tempbuf[modelNints];
   char *name;
-  serializeUnpack(buf, size, position, tempbuf, model_nints, CDI_DATATYPE_INT, context);
+  serializeUnpack(buf, size, position, tempbuf, modelNints, CDI_DATATYPE_INT, context);
   if (tempbuf[MODEL_PACK_INT_NAMELEN] != 0)
     {
       size_t len = (size_t) tempbuf[MODEL_PACK_INT_NAMELEN];