Fix building against latest Nix
Fix building against latest Nix

Fixes #8.
Fixes #9.

dtzWill/nix,bennofs/nix,ehmry/nix,pikajude/nix,pikajude/nix,pikajude/nix,NixOS/nix,dtzWill/nix,peti/nix,bennofs/nix,peti/nix,ehmry/nix,NixOS/nix,dezgeg/nix,vcunat/nix,layus/nix,layus/nix,dezgeg/nix,vcunat/nix,layus/nix,rycee/nix,shlevy/nix,dezgeg/nix,zimbatm/nix,shlevy/nix,zimbatm/nix,ehmry/nix,zimbatm/nix,dtzWill/nix,peti/nix,bennofs/nix,NixOS/nix,rycee/nix,rycee/nix,NixOS/nix,dtzWill/nix,rycee/nix,shlevy/nix,vcunat/nix,ehmry/nix,rycee/nix,layus/nix,ehmry/nix,dezgeg/nix,ehmry/nix,layus/nix,shlevy/nix,peti/nix,NixOS/nix,zimbatm/nix,bennofs/nix,vcunat/nix,dtzWill/nix,shlevy/nix,dezgeg/nix,peti/nix