Remove function pointer casting restriction

Cython/Compiler/ExprNodes.py

@@ -2600,10 +2600,6 @@ class TypecastNode(ExprNode):
     def analyse_types(self, env):
         base_type = self.base_type.analyse(env)
         _, self.type = self.declarator.analyse(base_type, env)
-        if self.type.is_cfunction:
-            error(self.pos,
-                "Cannot cast to a function type")
-            self.type = PyrexTypes.error_type
         self.operand.analyse_types(env)
         to_py = self.type.is_pyobject
         from_py = self.operand.type.is_pyobject