include Python.h first

[cxzhong]

It seems CPython document said

Note Since Python may define some pre-processor definitions which affect the standard headers on some systems, you must include Python.h before any standard headers are included.
It is recommended to always define PY_SSIZE_T_CLEAN before including Python.h. See [Parsing arguments and building values](https://docs.python.org/3/c-api/arg.html#arg-parsing) for a description of this macro.

[tornaria]

I don't know what is broken without this, but ok.

[cxzhong]

I also do not find something is broken, but in the document, Python.h is included first, then system headers, standard libs are included