Disable GC until VM objects get initialized [Bug #16616]

gc.c

@@ -1623,6 +1623,7 @@ rb_objspace_alloc(void)
     malloc_limit = gc_params.malloc_limit_min;
     list_head_init(&objspace->eden_heap.pages);
     list_head_init(&objspace->tomb_heap.pages);
+    dont_gc = TRUE;
 
     return objspace;
 }

test/ruby/test_thread.rb

@@ -1150,6 +1150,7 @@ q.pop
                     "0 thread_machine_stack_size")
     assert_operator(h_default[:thread_machine_stack_size], :<=, h_large[:thread_machine_stack_size],
                     "large thread_machine_stack_size")
+    assert_equal("ok", invoke_rec('print :ok', 1024 * 1024 * 100, nil, false))
   end
 
   def test_vm_machine_stack_size

vm.c

@@ -3345,6 +3345,8 @@ Init_vm_objects(void)
     vm->mark_object_ary = rb_ary_tmp_new(128);
     vm->loading_table = st_init_strtable();
     vm->frozen_strings = st_init_table_with_size(&rb_fstring_hash_type, 10000);
+
+    rb_objspace_gc_enable(vm->objspace);
 }
 
 /* top self */