[Bug target/107315] support 128bit long double on aarch64 darwin

[hengxu at bao dot ac.cn]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107315

--- Comment #4 from hengxu010 <hengxu at bao dot ac.cn> ---
Hi Iain , thank you very much! I'm very happy to hear that you have'd already
implement the support for 16 bite float type in the development version of gcc,
I can try that later. Hope the official version can be online soon. And thank
you for taking time for answering these questions.