py: Add basic _thread module, with ability to start a new thread.
diff --git a/py/objmodule.c b/py/objmodule.c
index 6d4b479..dc2ce78 100644
--- a/py/objmodule.c
+++ b/py/objmodule.c
@@ -160,6 +160,9 @@
 #if MICROPY_PY_GC && MICROPY_ENABLE_GC
     { MP_ROM_QSTR(MP_QSTR_gc), MP_ROM_PTR(&mp_module_gc) },
 #endif
+#if MICROPY_PY_THREAD
+    { MP_ROM_QSTR(MP_QSTR__thread), MP_ROM_PTR(&mp_module_thread) },
+#endif
 
     // extmod modules