ompi/hook: Add the hook/license framework

* Include a 'demo' component that shows some of the features.
 * Currently has hooks for:
   - MPI_Initialized
     - top, bottom
   - MPI_Init_thread
     - top, bottom
   - MPI_Finalized
     - top, bottom
   - MPI_Init
     - top (pre-opal_init), top (post-opal_init), error, bottom
   - MPI_Finalize
     - top, bottom
 * Other places in ompi can 'register' to hook into any one of these places
   by passing back a component structure filled with function pointers.
 * Add a `MCA_BASE_COMPONENT_FLAG_REQUIRED` flag to the MCA structure that
   is checked by the `hook` framework. If a required, static component has
   been excluded then the `hook` framework will fail to initialize.
   - See note in `opal/mca/mca.h` as to why this is checked in the `hook`
     framework and not in `opal/mca/base/mca_base_component_find.c`

Signed-off-by: Joshua Hursey <jhursey@us.ibm.com>

ompi/runtime/ompi_mpi_finalize.c

@@ -82,6 +82,7 @@
 #include "ompi/runtime/params.h"
 #include "ompi/dpm/dpm.h"
 #include "ompi/mpiext/mpiext.h"
+#include "ompi/mca/hook/base/base.h"
 
 #if OPAL_ENABLE_FT_CR == 1
 #include "ompi/mca/crcp/crcp.h"
@@ -110,6 +111,8 @@ int ompi_mpi_finalize(void)
     OPAL_TIMING_DECLARE(tm);
     OPAL_TIMING_INIT_EXT(&tm, OPAL_TIMING_GET_TIME_OF_DAY);
 
+    ompi_hook_base_mpi_finalize_top();
+
     /* Be a bit social if an erroneous program calls MPI_FINALIZE in
        two different threads, otherwise we may deadlock in
        ompi_comm_free() (or run into other nasty lions, tigers, or
@@ -487,6 +490,12 @@ int ompi_mpi_finalize(void)
         goto done;
     }
 
+    /* Now close the hook framework */
+    if (OMPI_SUCCESS != (ret = mca_base_framework_close(&ompi_hook_base_framework) ) ) {
+        OMPI_ERROR_LOG(ret);
+        goto done;
+    }
+
     if (OPAL_SUCCESS != (ret = opal_finalize_util())) {
         goto done;
     }
@@ -506,6 +515,7 @@ int ompi_mpi_finalize(void)
 
  done:
     opal_mutex_unlock(&ompi_mpi_bootstrap_mutex);
+    ompi_hook_base_mpi_finalize_bottom();
 
     return ret;
 }