Merge pull request #892 from grahamc/hydra-queue-runner-build-one

Dependencies

• [2] HTDANBLN Merge pull request #730 from NixOS/flake
• [3] MHVIT4JY Split hydra-queue-runner.cc more
• [4] U55WNIDP Abort unsupported build steps
• [5] SSOJX6VZ hydra-queue-runner: --build-one: correctly handle a cached build
• [6] OBOTGFG6 Prevent orphaned build steps
• [7] EBJP3MNA Build against nix-master
• [8] NJXD2ABJ Abort unsupported build steps

Change contents

• edit in src/hydra-queue-runner/builder.cc at line 151
  [3.4942]→[3.1:1](∅→∅)
  −
• edit in src/hydra-queue-runner/builder.cc at line 380
  [3.88]→[2.1:1](∅→∅)
  −