7zz: cross-compile for mingw

[AtnNn]

Description of changes

Fixes all build errors in pkgsCross.mingwW64._7zz on x86_64 Linux.

$ nix-shell -p nixpkgs-review --run "nixpkgs-review rev HEAD"
$ wine result/bin/7zz.exe
7-Zip (z) 22.01 (x64) : Copyright (c) 1999-2022 Igor Pavlov : 2022-07-15
Usage: 7zz <command> [<switches>...] <archive_name> [<file_names>...] [@listfile]
[...]

Things done

• Built on platform(s)
  • x86_64-linux
  • aarch64-linux
  • x86_64-darwin
  • aarch64-darwin
• For non-Linux: Is sandbox = true set in nix.conf? (See Nix manual)
• Tested, as applicable:
  • NixOS test(s) (look inside nixos/tests)
  • and/or package tests
  • or, for functions and "core" functionality, tests in lib/tests or pkgs/test
  • made sure NixOS tests are linked to the relevant packages
• Tested compilation of all packages that depend on this change using nix-shell -p nixpkgs-review --run "nixpkgs-review rev HEAD". Note: all changes have to be committed, also see nixpkgs-review usage
• Tested basic functionality of all binary files (usually in ./result/bin/)
• 23.05 Release Notes (or backporting 22.11 Release notes)
  • (Package updates) Added a release notes entry if the change is major or breaking
  • (Module updates) Added a release notes entry if the change is significant
  • (Module addition) Added a release notes entry if adding a new NixOS module
• Fits CONTRIBUTING.md.

[flokli]

Successfully compiled nix-build -A pkgsCross.mingwW64._7zz and pkgsCross.mingw32._7zz.

I tried running the resulting result/bin/7zz.exe, with wine/wine64, but they complained about mcfgthread-12.dll. I'd assume that library is available on a real windows, so I didn't test any further :-D

[06kellyjac]

Thanks for working on this.

One question though. Is platforms.windows correct here?

nix-repl> lib.platforms.windows
[ "i686-cygwin" "x86_64-cygwin" "x86_64-windows" "i686-windows" ]

I don't know much about windows builds but it seems like Cygwin is a bit different to MinGW
Is "x86_64-cygwin" actually under isMinGW?

isCygwin       = { kernel = kernels.windows; abi = abis.cygnus; };
isMinGW        = { kernel = kernels.windows; abi = abis.gnu; };

[AtnNn]

Cygwin and MinGW are indeed very different. I don't think it matters here because platforms.unix already includes Cygwin.

[06kellyjac]

so it should have stayed platforms.unix and not added platforms.windows?

[AtnNn]

The two mingw doubles were needed, which platforms.windows provides.

[AtnNn]

Your question makes sense. Perhaps there should be a platforms.mingw, using that would have made the intention of the change clearer.