fix compilation with cygwin

theano/gof/cmodule.py

@@ -1380,7 +1380,7 @@ def get_module_cache(dirname, init_args=None):
 
 def get_lib_extension():
     """Return the platform-dependent extension for compiled modules."""
-    if sys.platform == 'win32':
+    if sys.platform in ['win32', 'cygwin']:
         return 'pyd'
     else:
         return 'so'