A simple fix for a subtle problem

TODO.FACTOR.txt

@@ -1,10 +1,3 @@
-- crash:
-  - start UI
-  - redefine new-size
-  - recompile all
-  - full gc
-  - crash!
-
 - unix i/o: problems with passing f to syscalls
 - if a primitive throws an error, :c doesn't show the call frame there
 - "benchmark/help": without a yield UI runs out of memory
@@ -63,6 +56,7 @@
 
 + ui:
 
+- fix listener scroll to
 - { } H{ } [ ] tabular-output -- excess newline
 - multiple listener-run-files is broken
 - word wrap in UI broken again

vm/gc.c

@@ -114,7 +114,7 @@ void collect_roots(void)
 		
 		collect_callstack(stacks->call_region,stacks->call);
 
-		if(stacks != stack_chain)
+		if(stacks->next != NULL)
 		{
 			collect_callframe_triple(&stacks->callframe,
 				&stacks->callframe_scan,&stacks->callframe_end);