how to use the struct "RangeFunction" in Postgres 9.6 ?

Hi all,
I am puzzled for how to use the struct "RangeFunction" in Postgres 9.6, the struct "RangeFunction" is not the same with 9.3.
Can someone help me how to write the function "make_RangeFunction"?

the code as below:
SelectStmt *stmt = makeNode(SelectStmt);
List *args = list_make1(makeStringConst($2, @2));
args = lappend(args, makeStringConst($3, @3));
stmt->targetList = list_make1(make_star_target(-1));
stmt->fromClause = list_make1(make_RangeFunction("function_name", args));
static Node* make_RangeFunction(const char *func_name, List *func_args)
{
RangeFunction *n = makeNode(RangeFunction);
.... (how to write this function)
}

Thanks,
wln