Commit the hg build identification patch from the pymigr repo.
diff --git a/Include/pythonrun.h b/Include/pythonrun.h
index 0c380e6..96a0e23 100644
--- a/Include/pythonrun.h
+++ b/Include/pythonrun.h
@@ -120,6 +120,8 @@
PyAPI_FUNC(const char *) _Py_svnversion(void);
PyAPI_FUNC(const char *) Py_SubversionRevision(void);
PyAPI_FUNC(const char *) Py_SubversionShortBranch(void);
+PyAPI_FUNC(const char *) _Py_hgidentifier(void);
+PyAPI_FUNC(const char *) _Py_hgversion(void);
/* Internal -- various one-time initializations */
PyAPI_FUNC(PyObject *) _PyBuiltin_Init(void);