qt6.qttranslations: bootstrap directly

[misuzu]

This fixes pkgsCross.aarch64-multiplatform.pkgsBuildHost.qt6.qttranslations, which is needed for cross-compiling packages like zenity.

Here how it looks like without this change:

% nix-build . -A pkgsCross.aarch64-multiplatform.pkgsBuildHost.qt6.qttranslations
<...................>
[275/282] Generating ../../nix/store/2qvpnrk3vhqz2scri09f6kq6hig83wng-qttranslations-6.9.0/translations/qtwebsockets_ja.qm
[276/282] Generating ../../nix/store/2qvpnrk3vhqz2scri09f6kq6hig83wng-qttranslations-6.9.0/translations/qtwebsockets_en.qm
[277/282] Generating ../../nix/store/2qvpnrk3vhqz2scri09f6kq6hig83wng-qttranslations-6.9.0/translations/qtwebsockets_de.qm
[278/282] Generating ../../nix/store/2qvpnrk3vhqz2scri09f6kq6hig83wng-qttranslations-6.9.0/translations/qtwebsockets_ko.qm
[279/282] Generating ../../nix/store/2qvpnrk3vhqz2scri09f6kq6hig83wng-qttranslations-6.9.0/translations/qtwebsockets_zh_CN.qm
[280/282] Generating ../../nix/store/2qvpnrk3vhqz2scri09f6kq6hig83wng-qttranslations-6.9.0/translations/qtwebsockets_uk.qm
[281/282] Generating ../../nix/store/2qvpnrk3vhqz2scri09f6kq6hig83wng-qttranslations-6.9.0/translations/qtwebsockets_pl.qm
[282/282] Generating ../../nix/store/2qvpnrk3vhqz2scri09f6kq6hig83wng-qttranslations-6.9.0/translations/qtwebsockets_ru.qm
Running phase: glibPreInstallPhase
Running phase: installPhase
install flags: -j16 install
[0/1] Install the project...
-- Install configuration: "Release"
-- Installing: /nix/store/2qvpnrk3vhqz2scri09f6kq6hig83wng-qttranslations-6.9.0/translations/assistant_ar.qm
CMake Error at src/translations/cmake_install.cmake:54 (file):
  file INSTALL cannot copy file
  "/build/qttranslations-everywhere-src-6.9.0/build//nix/store/2qvpnrk3vhqz2scri09f6kq6hig83wng-qttranslations-6.9.0/translations/assistant_ar.qm"
  to
  "/nix/store/2qvpnrk3vhqz2scri09f6kq6hig83wng-qttranslations-6.9.0/translations/assistant_ar.qm":
  Permission denied.
Call Stack (most recent call first):
  src/cmake_install.cmake:47 (include)
  cmake_install.cmake:47 (include)


FAILED: CMakeFiles/install.util
cd /build/qttranslations-everywhere-src-6.9.0/build && /nix/store/mp0vxkdnx5279fr2y6w1vhndzx92jh9k-cmake-3.31.6/bin/cmake -P cmake_install.cmake
ninja: build stopped: subcommand failed.

Tested by building

• pkgsCross.aarch64-multiplatform.zenity (depends on qt6.{qttools,qtwayland}: fix cross compilation #403830)

Related: 0597d86

Things done

• Built on platform(s)
  • x86_64-linux
  • aarch64-linux
  • x86_64-darwin
  • aarch64-darwin
• For non-Linux: Is sandboxing enabled in nix.conf? (See Nix manual)
  • sandbox = relaxed
  • sandbox = true
• 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/)
• 25.05 Release Notes (or backporting 24.11 and 25.05 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.

---

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[misuzu]

Before:

% nix-instantiate . -A pkgsCross.aarch64-multiplatform.pkgsBuildHost.qt6.qttranslations
warning: you did not specify '--add-root'; the result might be removed by the garbage collector
/nix/store/lbrfp7cbqr04g5fhmf8m82jyfw1nac7y-qttranslations-6.9.0.drv
% nix-instantiate . -A pkgsCross.aarch64-multiplatform.pkgsBuildBuild.qt6.qttranslations
warning: you did not specify '--add-root'; the result might be removed by the garbage collector
/nix/store/kdzf334vrx4765v6d645z680zlivwg5v-qttranslations-6.9.0.drv

After:

% nix-instantiate . -A pkgsCross.aarch64-multiplatform.pkgsBuildBuild.qt6.qttranslations
warning: you did not specify '--add-root'; the result might be removed by the garbage collector
/nix/store/kdzf334vrx4765v6d645z680zlivwg5v-qttranslations-6.9.0.drv
% nix-instantiate . -A pkgsCross.aarch64-multiplatform.pkgsBuildHost.qt6.qttranslations
warning: you did not specify '--add-root'; the result might be removed by the garbage collector
/nix/store/kdzf334vrx4765v6d645z680zlivwg5v-qttranslations-6.9.0.drv

See #246022 (comment)