fix thread.error pickling

this caused problems inside the multiprocessing module

from_cpython/Include/pyerrors.h

@@ -249,7 +249,7 @@ PyAPI_FUNC(void) _PyErr_BadInternalCall(const char *filename, int lineno) PYSTON
 
 /* Function to create a new exception */
 PyAPI_FUNC(PyObject *) PyErr_NewException(
-    char *name, PyObject *base, PyObject *dict) PYSTON_NOEXCEPT;
+    const char *name, PyObject *base, PyObject *dict) PYSTON_NOEXCEPT;
 PyAPI_FUNC(PyObject *) PyErr_NewExceptionWithDoc(
     char *name, char *doc, PyObject *base, PyObject *dict) PYSTON_NOEXCEPT;
 PyAPI_FUNC(void) PyErr_WriteUnraisable(PyObject *) PYSTON_NOEXCEPT;

from_cpython/Python/errors.c

@@ -551,7 +551,7 @@ PyErr_Format(PyObject *exception, const char *format, ...)
 
 
 PyObject *
-PyErr_NewException(char *name, PyObject *base, PyObject *dict)
+PyErr_NewException(const char *name, PyObject *base, PyObject *dict)
 {
     char *dot;
     PyObject *modulename = NULL;

src/runtime/builtin_modules/thread.cpp

@@ -244,11 +244,7 @@ void setupThread() {
     thread_lock_cls->giveAttr("locked_lock", thread_lock_cls->getattr(internStringMortal("locked")));
     thread_lock_cls->freeze();
 
-    ThreadError = BoxedClass::create(type_cls, Exception, NULL, Exception->attrs_offset, Exception->tp_weaklistoffset,
-                                     Exception->tp_basicsize, false, "error");
-    ThreadError->giveAttr("__module__", boxString("thread"));
-    ThreadError->freeze();
-
+    ThreadError = (BoxedClass*)PyErr_NewException("thread.error", NULL, NULL);
     thread_module->giveAttr("error", ThreadError);
 }
 }

test/tests/cPickle_test.py

@@ -46,3 +46,6 @@ for obj in [(1, 2), "hello world", u"hola world", 1.0, 1j, 1L, 2, {1:2}, set([3]
 import cStringIO
 StringIO = cPickle.loads(cPickle.dumps(cStringIO.StringIO))
 print type(StringIO())
+
+import thread
+print cPickle.loads(cPickle.dumps(thread.error))