cannot currently enable warning checks for C++ class definition syntax as...

cannot currently enable warning checks for C++ class definition syntax as there are incorrect warnings

tests/run/cpp_classes_def.pyx

-# cython: experimental_cpp_class_def=True
+# mode: run
 # tag: cpp
+#### tag: werror   # FIXME: fix spurious warnings and enable
+# cython: experimental_cpp_class_def=True
 
 cdef double pi
 from math import pi