qemu: 5.2.0 -> 6.0.0; adopt; broaden platforms
qemu: 5.2.0 -> 6.0.0; adopt; broaden platforms

Tested building qemu_kvm, qemu_full, and qemu_test on x86_64-linux.
Also tested booting a VM generated with nixos-rebuild build-vm.

I wasn't able to test building pkgsMusl.qemu_kvm, because of many
build failures in dependencies.

NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs