Snippets for x265 4.2 from Nix aarch64-linux

Sourced from https://hydra.nixos.org/log/an87hb28s703796y4cls3nq7ip9rf0vi-x265-4.2.drv.

• /build/x265_4.2/source/common/aarch64/mem-neon.h:318:18: warning: 'res' is used uninitialized [-Wuninitialized]
    318 |         vst1q_u16(dst, src[i]);
        |         ~~~~~~~~~^~~~~~~~~~~~~