CPython checks for stdarg.h as HAVE_STDARG_PROTOTYPES ¹ at some places ² but not at other places ³. Either this check should be repeated at every call site or should be removed all together, most compilers supports this nowadays (should be verified with buildbots).

cc @vstinner @tiran @erlend-aasland

Footnotes

1. https://github.com/python/cpython/blob/16a7e4a0b75080275bf12cfb71d54b01d85099b2/configure.ac#L5026 ↩

2. https://github.com/python/cpython/blob/16a7e4a0b75080275bf12cfb71d54b01d85099b2/Modules/_asynciomodule.c#L2646 ↩

3. https://github.com/python/cpython/blob/16a7e4a0b75080275bf12cfb71d54b01d85099b2/Objects/call.c#L557 ↩