diff --git a/Python/pythonrun.c b/Python/pythonrun.c
index ec9ed02..0b3935a 100644
--- a/Python/pythonrun.c
+++ b/Python/pythonrun.c
@@ -75,6 +75,7 @@
 int Py_InteractiveFlag; /* Needed by Py_FdIsInteractive() below */
 int Py_InspectFlag; /* Needed to determine whether to exit at SystemError */
 int Py_NoSiteFlag; /* Suppress 'import site' */
+int Py_BytesWarningFlag; /* Warn on str(bytes) and str(buffer) */
 int Py_UseClassExceptionsFlag = 1; /* Needed by bltinmodule.c: deprecated */
 int Py_FrozenFlag; /* Needed by getpath.c */
 int Py_IgnoreEnvironmentFlag; /* e.g. PYTHONPATH, PYTHONHOME */
@@ -234,6 +235,7 @@
 	if (pstderr == NULL)
 		Py_FatalError("Py_Initialize: can't set preliminary stderr");
 	PySys_SetObject("stderr", pstderr);
+	PySys_SetObject("__stderr__", pstderr);
 
 	_PyImport_Init();
 
@@ -261,8 +263,28 @@
 #endif /* WITH_THREAD */
 
 	warnings_module = PyImport_ImportModule("warnings");
-	if (!warnings_module)
+	if (!warnings_module) {
 		PyErr_Clear();
+	}
+	else {
+		PyObject *o;
+		char *action[8];
+
+		if (Py_BytesWarningFlag > 1)
+			*action = "error";
+		else if (Py_BytesWarningFlag)
+			*action = "default";
+		else
+			*action = "ignore";
+
+		o = PyObject_CallMethod(warnings_module,
+					"simplefilter", "sO",
+					*action, PyExc_BytesWarning);
+		if (o == NULL)
+			Py_FatalError("Py_Initialize: can't initialize"
+				      "warning filter for BytesWarning.");
+		Py_DECREF(o);
+        }
 
 #if defined(HAVE_LANGINFO_H) && defined(CODESET)
 	/* On Unix, set the file system encoding according to the
@@ -743,6 +765,7 @@
 	PySys_SetObject("stdout", std);
 	Py_DECREF(std);
 
+#if 1 /* Disable this if you have trouble debugging bootstrap stuff */
 	/* Set sys.stderr, replaces the preliminary stderr */
 	if (!(std = PyFile_FromFd(fileno(stderr), "<stderr>", "w", -1,
 				  NULL, "\n", 0))) {
@@ -751,6 +774,7 @@
         PySys_SetObject("__stderr__", std);
 	PySys_SetObject("stderr", std);
 	Py_DECREF(std);
+#endif
 
         if (0) {
   error:
@@ -1339,7 +1363,7 @@
 	PyArena *arena = PyArena_New();
 	if (arena == NULL)
 		return NULL;
-	
+
 	mod = PyParser_ASTFromString(str, "<string>", start, flags, arena);
 	if (mod != NULL)
 		ret = run_mod(mod, "<string>", globals, locals, flags, arena);
@@ -1356,7 +1380,7 @@
 	PyArena *arena = PyArena_New();
 	if (arena == NULL)
 		return NULL;
-	
+
 	mod = PyParser_ASTFromFile(fp, filename, NULL, start, 0, 0,
 				   flags, NULL, arena);
 	if (closeit)
@@ -1705,7 +1729,7 @@
 static void
 call_py_exitfuncs(void)
 {
-	if (pyexitfunc == NULL) 
+	if (pyexitfunc == NULL)
 		return;
 
 	(*pyexitfunc)();