--- a/src/symbols.c	Mon Aug 13 10:52:06 2007 +0200
+++ b/src/symbols.c	Mon Aug 13 10:52:53 2007 +0200
@@ -98,8 +98,6 @@
 
   ((markobj) (sym->value));
   ((markobj) (sym->function));
-  /* No need to mark through ->obarray, because it only holds nil or t.  */
-  /*((markobj) (sym->obarray));*/
   XSETSTRING (pname, sym->name);
   ((markobj) (pname));
   if (!symbol_next (sym))
@@ -192,17 +190,9 @@
   if (purify_flag && ! purified (str))
     str = make_pure_pname (XSTRING_DATA (str), len, 0);
   sym = Fmake_symbol (str);
-  /* FSFmacs places OBARRAY here, but it is pointless because we do
-     not mark through this slot, so it is not usable later (because
-     the obarray might have been collected).  Marking through the
-     ->obarray slot is an even worse idea, because it would keep
-     obarrays from being collected because of symbols pointed to them.
-
-     NOTE: We place Qt here only if OBARRAY is actually Vobarray.  It
-     is safer to do it this way, to avoid hosing with symbols within
-     pure objects.  */
-  if (EQ (obarray, Vobarray))
-    XSYMBOL (sym)->obarray = Qt;
+  /* FSFmacs places OBARRAY here, but it we know better.  See lisp.h
+     for a little explanation.  */
+  XSYMBOL_OBARRAY_FLAGS (sym) = 1 | (2 * EQ (Vobarray, obarray));
 
   if (SYMBOLP (*ptr))
     symbol_next (XSYMBOL (sym)) = XSYMBOL (*ptr);
@@ -287,7 +277,13 @@
 	    }
 	}
     }
-  XSYMBOL (tem)->obarray = Qnil;
+  if (XSYMBOL_OBARRAY_FLAGS (tem) & 4)
+    {
+      /* Symbol was stored somewhere in a pure structure, so it needs
+         at least one existing reference.  Make one.  */
+      Fputhash (tem, Qnil, Vpure_uninterned_symbol_table);
+    }
+  XSYMBOL_OBARRAY_FLAGS (tem) &= ~3;
   return Qt;
 }
 
@@ -561,7 +557,7 @@
 
   if (symbol_is_constant (sym, val)
       || (SYMBOL_IS_KEYWORD (sym) && !EQ (newval, sym)
-	  && !NILP (XSYMBOL (sym)->obarray)))
+	  && (XSYMBOL_OBARRAY_FLAGS (sym) & 2)))
     signal_error (Qsetting_constant,
 		  UNBOUNDP (newval) ? list1 (sym) : list2 (sym, newval));
 }
@@ -3162,6 +3158,7 @@
   XSYMBOL (Qnil)->name->plist = Qnil;
   XSYMBOL (Qnil)->value = Qnil; /* Nihil ex nihil */
   XSYMBOL (Qnil)->plist = Qnil;
+  XSYMBOL_OBARRAY_FLAGS (Qnil) = 1 | 2;
 
   Vobarray = make_vector (OBARRAY_SIZE, Qzero);
   initial_obarray = Vobarray;
@@ -3170,7 +3167,6 @@
   {
     int hash = hash_string (string_data (XSYMBOL (Qnil)->name), 3);
     XVECTOR_DATA (Vobarray)[hash % OBARRAY_SIZE] = Qnil;
-    XSYMBOL (Qnil)->obarray = Qt;
   }
 
   {