Patch from Eric Norum <eric@cls.usask.ca> to make task variables maintain

a global and private version of each task variable.

c/src/exec/rtems/src/tasks.c

@@ -105,6 +105,8 @@ User_extensions_routine _RTEMS_tasks_Delete_extension(
     next = tvp->next;
     if  (tvp->dtor)
         (*tvp->dtor)( tvp->ptr );
+    if (executing == deleted)
+        *tvp->ptr = tvp->gval;
     _Workspace_Free( tvp );
     tvp = next;
   }
@@ -137,13 +139,15 @@ void _RTEMS_tasks_Switch_extension(
 
   tvp = executing->task_variables;
   while (tvp) {
-    tvp->var = *tvp->ptr;
+    tvp->tval = *tvp->ptr;
+    *tvp->ptr = tvp->gval;
     tvp = tvp->next;
   }
 
   tvp = heir->task_variables;
   while (tvp) {
-    *tvp->ptr = tvp->var;
+    tvp->gval = *tvp->ptr;
+    *tvp->ptr = tvp->tval;
     tvp = tvp->next;
   } 
 }

c/src/exec/rtems/src/taskvariableadd.c

@@ -72,7 +72,7 @@ rtems_status_code rtems_task_variable_add(
       _Thread_Enable_dispatch();
       return RTEMS_NO_MEMORY;
     }
-    new->var = 0;
+    new->gval = *ptr;
     new->ptr = ptr;
     new->dtor = dtor;
 

c/src/exec/rtems/src/taskvariableget.c

@@ -59,7 +59,7 @@ rtems_status_code rtems_task_variable_get(
 	 * Should this return the current (i.e not the
 	 * saved) value if `tid' is the current task?
 	 */
-        *result = tvp->var;
+        *result = tvp->tval;
         _Thread_Enable_dispatch();
         return RTEMS_SUCCESSFUL;
       }

c/src/exec/score/include/rtems/score/thread.h

@@ -94,7 +94,8 @@ struct rtems_task_variable_tt;
 struct rtems_task_variable_tt {
   struct rtems_task_variable_tt  *next;
   void                          **ptr;
-  void                           *var;
+  void                           *gval;
+  void                           *tval;
   void                          (*dtor)(void *);
 };