lib.systems, test.cross.sanity: add test case for #264989

[ghost]

Description of changes

We have several cross-compilation bugs that show up if hostPlatform!=buildPlatform yet hostPlatform.config==buildPlatform.config.

These bugs have appeared and disappeared as we've fiddled with the definition of equality for platform objects. This commit adds a clear-cut case where they are not equal and never will be, so we can test it.

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/)
• 23.11 Release Notes (or backporting 23.05 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.

[ghost]

@ofborg build pkgsCross.gnu64_simplekernel.bash

[ghost]

Should fail with

bash-5.2-p15-x86_64-unknown-linux-gnu> checking for x86_64-unknown-linux-gnu-gcc... x86_64-unknown-linux-gnu-gcc
bash-5.2-p15-x86_64-unknown-linux-gnu> checking whether the C compiler works... no
bash-5.2-p15-x86_64-unknown-linux-gnu> configure: error: in `/build/bash-5.2':
bash-5.2-p15-x86_64-unknown-linux-gnu> configure: error: C compiler cannot create executables
bash-5.2-p15-x86_64-unknown-linux-gnu> See `config.log' for more details
error: build of '/nix/store/fxlhkfq8lax6f2jmsh59vl4q8m8ig7az-bash-5.2-p15-x86_64-unknown-linux-gnu.drv' on 'ssh://root@192.168.22.101' failed: builder for '/nix/store/fxlhkfq8lax6f2jmsh59vl4q8m8ig7az-bash-5.2-p15-x86_64-unknown-linux-gnu.drv' failed with exit code 77
error: builder for '/nix/store/fxlhkfq8lax6f2jmsh59vl4q8m8ig7az-bash-5.2-p15-x86_64-unknown-linux-gnu.drv' failed with exit code 1;
       last 10 log lines:
       > checking build system type... x86_64-unknown-linux-gnu
       > checking host system type... x86_64-unknown-linux-gnu
       >
       > Beginning configuration for bash-5.2-release for x86_64-unknown-linux-gnu
       >
       > checking for x86_64-unknown-linux-gnu-gcc... x86_64-unknown-linux-gnu-gcc
       > checking whether the C compiler works... no
       > configure: error: in `/build/bash-5.2':
       > configure: error: C compiler cannot create executables
       > See `config.log' for more details
       For full logs, run 'nix log /nix/store/fxlhkfq8lax6f2jmsh59vl4q8m8ig7az-bash-5.2-p15-x86_64-unknown-linux-gnu.drv'.

[ghost]

Should fail with

Yep

[ghost]

Once #263082 merges we will get warned about stuff like this.

[ghost]

@ofborg build pkgsCross.gnu64_simplekernel.bash

[alyssais]

Could we use pkgsLLVM or something instead so we don't need to use a new example?

[ghost]

Could we use pkgsLLVM or something instead so we don't need to use a new example?

Unfortunately pkgsLLVM doesn't demonstrate the problem:

This will succeed:

@ofborg build pkgsLLVM.bash

This will fail:

@ofborg build pkgsCross.gnu64_simplekernel.bash