* gc.c (scm_igc): Don't call scm_i_thread_invalidate_freelists.

* gc.c (scm_gc_sweep): Call it here instead, which is a more
logical place.

* threads.c (create_thread): Remember root object until the handle
of the new thread is on all_threads list.

* root.c (scm_make_root): Moved copying of fluids until after
creation of root handle so that the fluids are GC protected.  Also
removed the critical section.

libguile/threads.c

@@ -411,6 +411,9 @@ create_thread (scm_t_catch_body body, void *body_data,
       all_threads = new_threads;
       thread_count++;
       scm_i_plugin_mutex_unlock (&thread_admin_mutex);
+
+      scm_remember_upto_here_1 (root);
+      
       scm_i_enter_guile (parent);
     }