They're optional-only for now (unlike in pure Python) but that's all
I needed.  The syntax can easily be relaxed if we want to support
required keyword-only arguments for extension types in the future.

Based on patch from Hervé Coatanhay.

Patch by Eric Snow.

Patch by Eric Snow.

allocating path buffers on the heap instead of the stack.

Based on patch from Hervé Coatanhay.

(Initial patch by Dionysios Kalofonos)

(Patch by Dionysios Kalofonos)

Closes #14250: regex.flags has not only explicit flags but also implicit flags and those from the pattern

3.2 explain json.dumps for non-string keys in dicts. closes issue6566. Patch contributed Kirubakaran Athmanathan