darwin: installing tmsu fails because of fuse buildInput

[ghost]

Issue description

I cannot install tmsu on macOS using nix-env -iA latest.tmsu:

installing 'tmsu-0.7.0'
error: Package ‘fuse-2.9.7’ in /nix/store/p0ww35zx7jacxpsly5dxrz8r547krxsk-latest/latest/pkgs/os-specific/linux/fuse/common.nix:77 is not supported on ‘x86_64-darwin’, refusing to evaluate.

I'd guess because buildInputs specifies fuse, while platforms indicates all:
https://github.com/NixOS/nixpkgs/blob/master/pkgs/tools/filesystems/tmsu/default.nix#L59

Technical details

• system: "x86_64-darwin"
• host os: Darwin 17.4.0, macOS 10.13.3
• multi-user?: yes
• sandbox: no
• version: nix-env (Nix) 2.0
• channels(root): "nixpkgs-18.03pre129212.098c7f3d945"
• channels(efx): "nixpkgs-latest, latest"
• nixpkgs: /nix/var/nix/profiles/per-user/root/channels/nixpkgs

[matthewbauer]

So we don’t have osxfuse packaged yet. This gets difficult because we don’t have a way to install kernel drivers yet.

/cc @LnL7

And LnL7/nix-darwin#54

[LnL7]

I have no idea how much work it would be to package osxfuse or how useful the result is in practice.

[ghost]

Interesting. I propose we modify platforms to be linux specific then.