Properly cast the list_item_t

Technically, the object is a "struct pmix_list_item_t*" in
the pmix_list_t definition because the actual list item
object hasn't been defined yet when we defined the list
structure. So when we access it, we should cast to the
defined object.

Signed-off-by: Ralph Castain <rhc@pmix.org>

Author: rhc54

src/class/pmix_list.h

@@ -670,7 +670,7 @@ static inline pmix_list_item_t *pmix_list_remove_first(pmix_list_t *list)
     list->pmix_list_length--;
 
     /* get pointer to first element on the list */
-    item = list->pmix_list_sentinel.pmix_list_next;
+    item = (pmix_list_item_t*)list->pmix_list_sentinel.pmix_list_next;
 
     /* reset previous pointer of next item on the list */
     item->pmix_list_next->pmix_list_prev = item->pmix_list_prev;
@@ -731,7 +731,7 @@ static inline pmix_list_item_t *pmix_list_remove_last(pmix_list_t *list)
     list->pmix_list_length--;
 
     /* get item */
-    item = list->pmix_list_sentinel.pmix_list_prev;
+    item = (pmix_list_item_t*)list->pmix_list_sentinel.pmix_list_prev;
 
     /* reset previous pointer on next to last pointer */
     item->pmix_list_prev->pmix_list_next = item->pmix_list_next;