Issue #15784: Modify OSError.__str__() to better distinguish between
errno error numbers and Windows error numbers.
diff --git a/Objects/exceptions.c b/Objects/exceptions.c
index 74bb262..6b04700 100644
--- a/Objects/exceptions.c
+++ b/Objects/exceptions.c
@@ -1016,12 +1016,12 @@
 #ifdef MS_WINDOWS
     /* If available, winerror has the priority over myerrno */
     if (self->winerror && self->filename)
-        return PyUnicode_FromFormat("[Error %S] %S: %R",
+        return PyUnicode_FromFormat("[WinError %S] %S: %R",
                                     self->winerror ? self->winerror: Py_None,
                                     self->strerror ? self->strerror: Py_None,
                                     self->filename);
     if (self->winerror && self->strerror)
-        return PyUnicode_FromFormat("[Error %S] %S",
+        return PyUnicode_FromFormat("[WinError %S] %S",
                                     self->winerror ? self->winerror: Py_None,
                                     self->strerror ? self->strerror: Py_None);
 #endif