use more recent JSLinux image

Hello!

As of 2021 (according to https://bellard.org/jslinux/news.html ) the original JSLinux comes with a newer version of Busybox, which has a nicer vi (eg implements the undo command, you can delete newlines with backspace, etc.) , and also the linux image  provides gcc.

Could you modify JSLinux mobile to support this new version?

Thanks!