portability: <' and >' are not always defined on addresses.

Specifically, don't sort objects by their memory addresses when
they're not allocated in the same array or other object.  Though
I haven't found a test case where that fails on my platform, C
says the behavior is undefined.
* src/AnnotationList.c (AnnotationList__insertInto): Remove
FIXME.  Use new id field of InadequacyList nodes rather than
their memory addresses when sorting.
(AnnotationList__compute_from_inadequacies): Add
inadequacy_list_node_count argument to pass to
InadequacyList__new_conflict.
* src/AnnotationList.h
(AnnotationList__compute_from_inadequacies): Update prototype
and documentation for new argument.
* src/InadequacyList.c (InadequacyList__new_conflict): Add
node_count argument and use it to assign a unique ID.
* src/InadequacyList.h (InadequacyListNodeCount): New typedef.
(InadequacyList): Add id field.
(InadequacyList__new_conflict): Update prototype and
documentation for new argument.
* src/ielr.c (ielr_compute_annotation_lists): Update
AnnotationList__compute_from_inadequacies invocation.

src/InadequacyList.c

@@ -27,9 +27,12 @@ ContributionIndex const ContributionIndex__error_action = -2;
 
 InadequacyList *
 InadequacyList__new_conflict (state *manifesting_state, symbol *token,
-                              bitset actions)
+                              bitset actions,
+                              InadequacyListNodeCount *node_count)
 {
   InadequacyList *result = xmalloc (sizeof *result);
+  result->id = (*node_count)++;
+  aver (*node_count != 0);
   result->next = NULL;
   result->manifestingState = manifesting_state;
   result->contributionCount = bitset_count (actions);