In reply to @opna2608:matrix.org
if you have the hardware + a linux and nix installation then you can checkout the branch and try building i.e. stdenv or hello from it. if you don't have the hardware and/or setup then you can add boot.binfmt.emulatedSystems = [ "powerpc64-linux" ] to the nixos config of some other system and test stdenv or hello with --argstr localSystem powerpc64-linux

In reply to @opna2608:matrix.org
the latter doesn't really work fully due to emulation-related test failures, but it gets very far along

for the sake of mentioning the exact failure: it will die on diffutils tests:

FAIL: test-sigsegv-catch-stackoverflow1
=======================================

qemu: uncaught target signal 11 (Segmentation fault) - core dumped
FAIL test-sigsegv-catch-stackoverflow1 (exit status: 139)

works fine on hardware though

    pythonAbiName =
      # python's build doesn't support every gnu<extension>, and doesn't
      # differentiate between musl and glibc, so we list those supported in
      # here:
      # https://github.com/python/cpython/blob/e488e300f5c01289c10906c2e53a8e43d6de32d8/configure.ac#L724
      # Note: this is an approximation, as it doesn't take into account the CPU
      # family, or the nixpkgs abi naming conventions.
      if elem gnuAbiName [
        "gnux32"
        "gnueabihf"
        "gnueabi"
        "gnuabin32"
        "gnuabi64"
        "gnuspe"
      ]
      then gnuAbiName
      else "gnu";