Description:
------------
FFI causes a segfault if called with variadics.

Test script:
---------------
<?php

$libc = FFI::cdef("int printf(const char *format, ...);", "libc.so.6");
$args = ["test"];
$libc->printf(...$args);

Expected result:
----------------
test

Actual result:
--------------
Segmentation fault:

Program received signal SIGSEGV, Segmentation fault.
0x0000555555b0826a in zend_check_arg_send_type (zf=0x55555659b710 <executor_globals+1296>, arg_num=0, mask=3) at Zend/zend_compile.h:943
943             return UNEXPECTED((zf->common.arg_info[arg_num].pass_by_reference & mask) != 0);