Switch calling convention of string.replace() away from varargs

from_cpython/Objects/stringobject.c

@@ -899,14 +899,19 @@ replace(PyStringObject *self,
     }
 }
 
-PyObject* string_replace(PyStringObject *self, PyObject *args)
+// Pyston change: don't use varags calling convention
+// PyObject* string_replace(PyStringObject *self, PyObject *args)
+PyObject* string_replace(PyStringObject *self, PyObject *from, PyObject* to, PyObject** args)
 {
+    PyObject* _count = args[0];
     Py_ssize_t count = -1;
-    PyObject *from, *to;
     const char *from_s, *to_s;
     Py_ssize_t from_len, to_len;
 
-    if (!PyArg_ParseTuple(args, "OO|n:replace", &from, &to, &count))
+    // Pyston change: don't use varags calling convention
+    // if (!PyArg_ParseTuple(args, "OO|n:replace", &from, &to, &count))
+    //    return NULL;
+    if (_count && !PyArg_ParseSingle(_count, 3, "replace", "n", &count))
         return NULL;
 
     if (PyString_Check(from)) {

src/runtime/str.cpp

@@ -2780,7 +2780,7 @@ static PyMethodDef string_methods[] = {
     { "rindex", (PyCFunction)string_rindex, METH_VARARGS, NULL },
     { "rfind", (PyCFunction)string_rfind, METH_VARARGS, NULL },
     { "expandtabs", (PyCFunction)string_expandtabs, METH_VARARGS, NULL },
-    { "replace", (PyCFunction)string_replace, METH_VARARGS, NULL },
+    { "replace", (PyCFunction)string_replace, METH_O3 | METH_D1, NULL },
     { "splitlines", (PyCFunction)string_splitlines, METH_VARARGS, NULL },
     { "zfill", (PyCFunction)string_zfill, METH_VARARGS, NULL },
     { "__format__", (PyCFunction)string__format__, METH_VARARGS, NULL },