Improve OMPT code: remove use of assignment to multiple struct fields using .fieldname

[jmellorcrummey]

Summary

Remove use of assignment to multiple struct fields using .fieldname syntax. This doesn't work with gcc 4.8 and earlier.
Replace with elementwise field assignments.

[jmellorcrummey]

Remove use of assignment to multiple struct fields using .fieldname syntax. This doesn't work with gcc 4.8 and earlier.
Replace with elementwise field assignments.

[omalyshe]

LGTM.

runtime/src/kmp_tasking.c

 //   OMPT will be used or not when the serial task is initialized. This function provides the support
 //   needed to initialize OMPT for the serial task after the fact.
 
 void
 __kmp_task_init_ompt( kmp_taskdata_t * task, int tid )
 {
     task->ompt_task_info.task_id = __ompt_task_id_new(tid);
     task->ompt_task_info.function = NULL;
-    task->ompt_task_info.frame = (ompt_frame_t) {
-        .exit_runtime_frame = NULL,
-        .reenter_runtime_frame = NULL
-    };
+    task->ompt_task_info.frame.exit_runtime_frame = NULL;
+    task->ompt_task_info.frame.reenter_runtime_frame = NULL;
 }
 #endif
 
 
 //----------------------------------------------------------------------------------------------------
 // __kmp_init_implicit_task: Initialize the appropriate fields in the implicit task for a given thread
 //
 // loc_ref:  reference to source location of parallel region
#endif
 
     KA_TRACE(20, ("__kmp_task_alloc(exit): T#%d created task %p parent=%p\n",
                   gtid, taskdata, taskdata->td_parent) );
 
 #if OMPT_SUPPORT
     if (ompt_status & ompt_status_track) {
         taskdata->ompt_task_info.task_id = __ompt_task_id_new(gtid);
         taskdata->ompt_task_info.function = (void*) task_entry;
-        taskdata->ompt_task_info.frame = (ompt_frame_t)
-            { .exit_runtime_frame = NULL, .reenter_runtime_frame = NULL };
+        taskdata->ompt_task_info.frame.exit_runtime_frame = NULL; 
+        taskdata->ompt_task_info.frame.reenter_runtime_frame = NULL;
     }
 #endif
 
     return task;
 }
 
 
 kmp_task_t *