makeWrapper doesn't cross-compile to windows

[Radvendii]

Describe the bug
makeWrapper depends on bash, which doesn't build for windows (see #119206)
It makes sense that bash doesn't build for windows, since it's not supported, and it makes sense that makeWrapper depends on bash, since that's how the wrapper is run.

The problem is many packages depend on makeWrapper, including many libraries which also happen to build executables. What should be done about this? Should we build something into makeWrapper that just no-ops when cross-compiling to windows? Is there a way to get that same functionality working on windows?

see also #120076, where i fixed a specific instance of this

To Reproduce
Steps to reproduce the behavior:

1. build something that uses makeWrapper for windows (e.g. nix-build '<nixpkgs>' --arg crossSystem '{ config = "x86_64-w64-mingw32"; libc = "msvcrt"; }' -A smpeg2
2. it tries to build "hook", which tries to build bash and fails

Expected behavior
The package would build at least the library. Not sure if the executables are just not workable or if there's some way to get them working on windows.

Metadata

• system: "x86_64-linux"
• host os: Linux 5.10.27, NixOS, 21.05pre281538.9e377a6ce42 (Okapi)
• multi-user?: yes
• sandbox: yes
• version: nix-env (Nix) 2.4pre20210326_dd77f71
• channels(root): "nixos-21.05pre281538.9e377a6ce42, nixos-hardware"
• channels(qolen): "home-manager"
• nixpkgs: /nix/var/nix/profiles/per-user/root/channels/nixos

Maintainer information:

# a list of nixpkgs attributes affected by the problem
attribute: makeWrapper
# a list of nixos modules affected by the problem
module:

[FRidh]

replace makewrapper with something creating a binary, such as #95569 (https://github.com/FRidh/make-binary-wrapper)

[Radvendii]

Ooh, thanks for the tip.
Is the idea there to replace all instances of makeWrapper with makeBinaryWrapper?
Also, how close are we to actually doing that?

[Mindavi]

I think it would be nice to convert makeWrapper over to makeBinaryWrapper for the whole of nixpkgs at some point. I feel there's still some discussion going on whether or not we want to do that for everything, but we probably want to since there's also other issues that are solved by makeBinaryWrapper (Darwin shebang issues).

[marius851000]

It is easy to replace every makeWrapper by makeBinarywrapper just by replacing the function in all-packages.nix.

It turns out makeBinaryWrapper doesn’t work directly out of the box for Windows, for seemingly 2 different reason:

1. there is no setenv function on Windows, but there is some equivalent, that can be quite easily put there.
2. execv seems to behave differently. In particular, it doesn’t seems to pass stdin. I’m trying to make this work with the CreateProcessA functions, but it’s more complicated, and requite generating a string command line where it doesn’t provide a function to convert from argv to an escaped string.

(Turns out execv is not even valid in Windows: https://learn.microsoft.com/en-gb/archive/blogs/twistylittlepassagesallalike/everyone-quotes-command-line-arguments-the-wrong-way)