Provide rustc version checking and installation in build.sh as building SDL requires rustc version 1.49 upto and including 1.63.
[The Arch package has a hacky work-around to guarantee installation of 1.63 here](https://git.hush.is/jahway603/AUR-packages/src/branch/master/silentdragonlite/PKGBUILD#L25), so perhaps we can come up with some logic using rustup.
* Ubuntu 20.04 has 1.61.0 in it's package manager
* Debian 11 has 1.48 in it's package manager
Provide rustc version checking and installation in build.sh as building SDL requires rustc version 1.49 upto and including 1.63.
The Arch package has a hacky work-around to guarantee installation of 1.63 here, so perhaps we can come up with some logic using rustup.
This is a good idea.