silence a C compiler warning for trivial generators that do not use their...

silence a C compiler warning for trivial generators that do not use their closure class cast (seems to be difficult to avoid such cases)

Cython/Compiler/Nodes.py

@@ -4095,6 +4095,9 @@ class GeneratorBodyDefNode(DefNode):
                 lenv.scope_class.type.declaration_code(Naming.cur_scope_cname),
                 lenv.scope_class.type.cast_code('%s->closure' %
                                                 Naming.generator_cname)))
+            # FIXME: this silences a potential "unused" warning => try to avoid unused closures in more cases
+            code.putln("if (1); else %s = %s;" % (
+                Naming.cur_scope_cname, Naming.cur_scope_cname))
 
         code.mark_pos(self.pos)
         code.putln("")