rust-chg: collect server flags from command arguments
This is the reimplementation of testsensitiveflag() and setcmdserverargs()
of chg.c.
Differential Revision: https://phab.mercurial-scm.org/D8380
#include <Python.h>
#if PY_MAJOR_VERSION >= 3
#define PYCODETYPE PyObject
#else
#define PYCODETYPE PyCodeObject
#endif
namespace contrib
{
void initpy(const char *cselfpath);
PyObject *pyglobals();
} /* namespace contrib */