A couple of DebugTransform fixes.

Cython/Compiler/ParseTreeTransforms.py

@@ -2937,6 +2937,7 @@ class DebugTransform(CythonTransform):
 
     def visit_NameNode(self, node):
         if (self.register_stepinto and
+            node.type is not None and
             node.type.is_cfunction and
             getattr(node, 'is_called', False) and
             node.entry.func_cname is not None):

Cython/Debugger/DebugWriter.py

@@ -42,7 +42,7 @@ class CythonDebugWriter(object):
         if etree is None:
             raise Errors.NoElementTreeInstalledException()
 
-        self.output_dir = os.path.join(output_dir, 'cython_debug')
+        self.output_dir = os.path.join(output_dir or os.curdir, 'cython_debug')
         self.tb = etree.TreeBuilder()
         # set by Cython.Compiler.ParseTreeTransforms.DebugTransform
         self.module_name = None