work around PyPy not supporting PySet_Size() in frozenset objects

Cython/Compiler/Optimize.py

@@ -2197,7 +2197,7 @@ class OptimizeBuiltinCalls(Visitor.NodeRefCleanupMixin,
         Builtin.tuple_type     : "PyTuple_GET_SIZE",
         Builtin.dict_type      : "PyDict_Size",
         Builtin.set_type       : "PySet_Size",
-        Builtin.frozenset_type : "PySet_Size",
+        Builtin.frozenset_type : "__Pyx_PyFrozenSet_Size",
         }.get
 
     _ext_types_with_pysize = set(["cpython.array.array"])

Cython/Utility/ModuleSetupCode.c

@@ -96,10 +96,13 @@
 #if CYTHON_COMPILING_IN_PYPY
   #define __Pyx_PyUnicode_Concat(a, b)      PyNumber_Add(a, b)
   #define __Pyx_PyUnicode_ConcatSafe(a, b)  PyNumber_Add(a, b)
+  // PyPy doesn't handle frozenset() in PySet_Size()
+  #define __Pyx_PyFrozenSet_Size(s)         PyObject_Size(s)
 #else
   #define __Pyx_PyUnicode_Concat(a, b)      PyUnicode_Concat(a, b)
   #define __Pyx_PyUnicode_ConcatSafe(a, b)  ((unlikely((a) == Py_None) || unlikely((b) == Py_None)) ? \
       PyNumber_Add(a, b) : __Pyx_PyUnicode_Concat(a, b))
+  #define __Pyx_PyFrozenSet_Size(s)         PySet_Size(s)
 #endif
 
 #define __Pyx_PyString_FormatSafe(a, b)   ((unlikely((a) == Py_None)) ? PyNumber_Remainder(a, b) : __Pyx_PyString_Format(a, b))