penultimate phase of Neil Schemenauer's GC patches
update configure files (turn --with-cycle-gc on for beta release?)
diff --git a/config.h.in b/config.h.in
index c28e380..7b909ad 100644
--- a/config.h.in
+++ b/config.h.in
@@ -210,6 +210,9 @@
    (shared library plus accessory files). */
 #undef WITH_NEXT_FRAMEWORK
 
+/* Define if you want cycle garbage collection */
+#undef WITH_CYCLE_GC
+
 /* The number of bytes in an off_t. */
 #undef SIZEOF_OFF_T