Change:
<del> { stdenv, makeWrapper, </del> <ins> { stdenv, makeWrapper, buildEnv, </ins> git, subversion, mercurial, bazaar, cvs, unzip, curl, gnused, coreutils }: <del> stdenv.mkDerivation { name = "nix-prefetch-scripts"; buildInputs = [ makeWrapper ]; </del> <ins> let mkPrefetchScript = tool: src: deps: stdenv.mkDerivation { name = "nix-prefetch-${tool}"; buildInputs = [ makeWrapper ]; phases = [ "installPhase" "fixupPhase" ]; installPhase = '' mkdir -p $out/bin </ins> <del> phases = [ "installPhase" "fixupPhase" ]; installPhase = '' mkdir -p $out/bin function copyScript { local name=nix-prefetch-$1; local src=$2; </del> local wrapArgs="" <del> cp $src $out/bin/$name; for dep in ''${@:3}; do </del> <ins> cp ${src} $out/bin/$name; for dep in ${stdenv.lib.concatStringsSep " " deps}; do </ins> wrapArgs="$wrapArgs --prefix PATH : $dep/bin" done wrapArgs="$wrapArgs --prefix PATH : ${gnused}/bin" wrapArgs="$wrapArgs --set HOME : /homeless-shelter" wrapProgram $out/bin/$name $wrapArgs <del> } copyScript "hg" ${../../../build-support/fetchhg/nix-prefetch-hg} ${mercurial} copyScript "git" ${../../../build-support/fetchgit/nix-prefetch-git} ${git} ${coreutils} copyScript "svn" ${../../../build-support/fetchsvn/nix-prefetch-svn} ${subversion} copyScript "bzr" ${../../../build-support/fetchbzr/nix-prefetch-bzr} ${bazaar} copyScript "cvs" ${../../../build-support/fetchcvs/nix-prefetch-cvs} ${cvs} copyScript "zip" ${../../../build-support/fetchzip/nix-prefetch-zip} ${unzip} ${curl} ''; meta = with stdenv.lib; { description = "Collection of all the nix-prefetch-* scripts which may be used to obtain source hashes"; maintainers = with maintainers; [ bennofs ]; platforms = with stdenv.lib.platforms; unix; # Quicker to build than to download, I hope hydraPlatforms = []; </del> <ins> ''; preferLocalBuild = true; meta = with stdenv.lib; { description = "Script used to obtain source hashes for fetch${tool}"; maintainers = with maintainers; [ bennofs ]; platforms = stdenv.lib.platforms.unix; }; }; in rec { nix-prefetch-bzr = mkPrefetchScript "bzr" ../../../build-support/fetchbzr/nix-prefetch-bzr [bazaar]; nix-prefetch-cvs = mkPrefetchScript "cvs" ../../../build-support/fetchcvs/nix-prefetch-cvs [cvs]; nix-prefetch-git = mkPrefetchScript "git" ../../../build-support/fetchgit/nix-prefetch-git [git coreutils]; nix-prefetch-hg  = mkPrefetchScript "hg"  ../../../build-support/fetchhg/nix-prefetch-hg   [mercurial]; nix-prefetch-svn = mkPrefetchScript "svn" ../../../build-support/fetchsvn/nix-prefetch-svn [subversion]; nix-prefetch-zip = mkPrefetchScript "zip" ../../../build-support/fetchzip/nix-prefetch-zip [unzip curl]; nix-prefetch-scripts = buildEnv { name = "nix-prefetch-scripts"; paths = [ nix-prefetch-bzr nix-prefetch-cvs nix-prefetch-git nix-prefetch-hg nix-prefetch-svn nix-prefetch-zip ]; meta = with stdenv.lib; { description = "Collection of all the nix-prefetch-* scripts which may be used to obtain source hashes"; maintainers = with maintainers; [ bennofs ]; platforms = stdenv.lib.platforms.unix; }; </ins> }; }

Discussion:
It's frustrating to have to build all the version control systems (in master or another development branch without binary caches) when I just need to prefetch git :frowning:
Make the expression modular so you can disable those?
Implementation at: