Bugfix: Properly test for errors from PyLong_AsLong() in itertools.cycle.
ti can raise an exception even if PyLong_Check() has
succeeded.
diff --git a/Modules/itertoolsmodule.c b/Modules/itertoolsmodule.c
index d5336f2..e7a7fbe 100644
--- a/Modules/itertoolsmodule.c
+++ b/Modules/itertoolsmodule.c
@@ -2918,6 +2918,7 @@
     Py_ssize_t cnt = 0;
     PyObject *long_cnt = NULL;
     PyObject *long_step = NULL;
+    long step;
     static char *kwlist[] = {"start", "step", 0};
 
     if (!PyArg_ParseTupleAndKeywords(args, kwds, "|OO:count",
@@ -2955,9 +2956,11 @@
     assert(long_cnt != NULL && long_step != NULL);
 
     /* Fast mode only works when the step is 1 */
-    if (!PyLong_Check(long_step) ||
-        PyLong_AS_LONG(long_step) != 1) {
-            slow_mode = 1;
+    step = PyLong_AsLong(long_step);
+    if (step != 1) {
+        slow_mode = 1;
+        if (step == -1 && PyErr_Occurred())
+            PyErr_Clear();
     }
 
     if (slow_mode)