MPI-5 ABI fix for MPI_THREAD_* constants (noncontiguous)

[jeffhammond]

MPI never required the thread constants to be a contiguous set, although that happened to be true in MPICH and Open MPI. With the MPI-5 ABI, they will not be contiguous, so the following patch is required to fix Quicksilver.

diff --git a/src/utilsMpi.cc b/src/utilsMpi.cc
index 811d892..d0e51de 100644
--- a/src/utilsMpi.cc
+++ b/src/utilsMpi.cc
@@ -11,13 +11,21 @@
 
 #ifdef HAVE_MPI
 
+static const char* mpiThreadLevelName(int level)
+{
+   if (level == MPI_THREAD_SINGLE)     return "MPI_THREAD_SINGLE";
+   if (level == MPI_THREAD_FUNNELED)   return "MPI_THREAD_FUNNELED";
+   if (level == MPI_THREAD_SERIALIZED) return "MPI_THREAD_SERIALIZED";
+   if (level == MPI_THREAD_MULTIPLE)   return "MPI_THREAD_MULTIPLE";
+
+   return "unknown MPI thread level";
+}
+
 void mpiInit( int *argc, char ***argv)
 {
 
 #ifdef HAVE_OPENMP
    { // limit scope
-      char const* const provided_string[4] = \
-         {"MPI_THREAD_SINGLE","MPI_THREAD_FUNNELED","MPI_THREAD_SERIALIZED","MPI_THREAD_MULTIPLE"};
       int provided, required = MPI_THREAD_FUNNELED;
       
       int err = MPI_Init_thread(argc, argv, required, &provided);
@@ -26,12 +34,12 @@ void mpiInit( int *argc, char ***argv)
       int rank = -1;
       mpiComm_rank(MPI_COMM_WORLD, &rank);
       if (rank == 0)
-         fprintf(stdout,"MPI Initialized         : %s\n", provided_string[provided]); 
+         fprintf(stdout,"MPI Initialized         : %s\n", mpiThreadLevelName(provided));
 
       if ((required > MPI_THREAD_SINGLE) && (required > provided))
       {
          printf("MPI-OpenMP Error.\n\tCode requires %s thread support. MPI library provides %s support.\n",
-                provided_string[required],provided_string[provided]);
+                mpiThreadLevelName(required), mpiThreadLevelName(provided));
          qs_assert(false);
       }
    } // limit scope