remove a bunch of needless scm_permanent_object calls

* libguile/array-handle.c:
* libguile/bytevectors.c:
* libguile/deprecated.c:
* libguile/eval.c:
* libguile/feature.c:
* libguile/filesys.c:
* libguile/gc.c:
* libguile/gdbint.c:
* libguile/goops.c:
* libguile/instructions.c:
* libguile/load.c:
* libguile/modules.c:
* libguile/numbers.c:
* libguile/options.c:
* libguile/ports.c:
* libguile/scmsigs.c:
* libguile/srcprop.c:
* libguile/srfi-4.c:
* libguile/stacks.c:
* libguile/threads.c:
* libguile/vm.c: Remove calls to scm_permanent_object, as they are no
  longer needed with the BDW GC.

libguile/gdbint.c

@@ -166,7 +166,7 @@ gdb_read (char *str)
 	}
     }
   gdb_result = ans;
-  /* Protect answer from future GC */
+  /* Protect answer from future GC (FIXME: still needed with BDW-GC?) */
   if (SCM_NIMP (ans))
     scm_permanent_object (ans);
 exit: