Darwin: utilities from Nixpkgs #706

Job	Run time
pkgs-linux: nixpkgs: build	3m 1s
pkgs-linux: nixpkgs: prebuilt	5m 29s
pkgs-linux: haskell-nix: build	2m 4s
pkgs-linux: haskell-nix: prebuilt	2m 9s
pkgs-linux: shajra: build	2m 31s
pkgs-linux: shajra: prebuilt	1m 59s
installers-linux	15s
pkgs-darwin: nixpkgs: build	4m 44s
pkgs-darwin: nixpkgs: prebuilt	15m 34s
pkgs-darwin: haskell-nix: build	3m 5s
pkgs-darwin: haskell-nix: prebuilt	5m 22s
pkgs-darwin: shajra: build	6m 32s
pkgs-darwin: shajra: prebuilt	4m 42s
	57m 27s

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