build-support: Simplify tmpdir creation with coreutils

macOS 10.12 doesn't have a usable --tmpdir flag on the builtin mktemp, but we can
make use of coreutil's mktemp instead.

pkgs/build-support/docker/nix-prefetch-docker

···
 
 # nix>=2.20 rejects adding symlinked paths to the store, so use realpath
 # to resolve to a physical path. https://github.com/NixOS/nix/issues/11941
-tmpPath="$(realpath "$(mktemp -d "${TMPDIR:-/tmp}/skopeo-copy-tmp-XXXXXXXX")")"
+tmpPath="$(realpath "$(mktemp -d --tmpdir skopeo-copy-tmp-XXXXXXXX)")"
 trap "rm -rf \"$tmpPath\"" EXIT
 
 tmpFile="$tmpPath/$(get_name $finalImageName $finalImageTag)"

pkgs/build-support/docker/nix-prefetch-docker.nix

···
-{ lib, stdenv, makeWrapper, nix, skopeo, jq }:
+{ lib, stdenv, makeWrapper, nix, skopeo, jq, coreutils }:
 
 stdenv.mkDerivation {
   name = "nix-prefetch-docker";
···
   installPhase = ''
     install -vD ${./nix-prefetch-docker} $out/bin/$name;
     wrapProgram $out/bin/$name \
-      --prefix PATH : ${lib.makeBinPath [ nix skopeo jq ]} \
+      --prefix PATH : ${lib.makeBinPath [ nix skopeo jq coreutils ]} \
       --set HOME /homeless-shelter
   '';
 

pkgs/build-support/fetchbzr/nix-prefetch-bzr

···
 if test -z "$finalPath"; then
     # nix>=2.20 rejects adding symlinked paths to the store, so use realpath
     # to resolve to a physical path. https://github.com/NixOS/nix/issues/11941
-    tmpPath="$(realpath "$(mktemp -d "${TMPDIR:-/tmp}/bzr-checkout-tmp-XXXXXXXX")")"
+    tmpPath="$(realpath "$(mktemp -d --tmpdir bzr-checkout-tmp-XXXXXXXX)")"
     trap "rm -rf \"$tmpPath\"" EXIT
 
     tmpFile="$tmpPath/$dstFile"

pkgs/build-support/fetchcvs/nix-prefetch-cvs

···
 mkTempDir() {
     # nix>=2.20 rejects adding symlinked paths to the store, so use realpath
     # to resolve to a physical path. https://github.com/NixOS/nix/issues/11941
-    tmpPath="$(realpath "$(mktemp -d "${TMPDIR:-/tmp}/nix-prefetch-cvs-XXXXXXXX")")"
+    tmpPath="$(realpath "$(mktemp -d --tmpdir nix-prefetch-csv-XXXXXXXX)")"
     trap removeTempDir EXIT
 }
 

pkgs/build-support/fetchgit/nix-prefetch-git

···
     # If we don't know the hash or a path with that hash doesn't exist,
     # download the file and add it to the store.
     if test -z "$finalPath"; then
-
         # nix>=2.20 rejects adding symlinked paths to the store, so use realpath
         # to resolve to a physical path. https://github.com/NixOS/nix/issues/11941
-        tmpPath="$(realpath "$(mktemp -d "${TMPDIR:-/tmp}/git-checkout-tmp-XXXXXXXX")")"
+        tmpPath="$(realpath "$(mktemp -d --tmpdir git-checkout-tmp-XXXXXXXX)")"
         exit_handlers+=(remove_tmpPath)
 
         tmpFile="$tmpPath/$(url_to_name "$url" "$rev")"

pkgs/build-support/fetchhg/nix-prefetch-hg

···
 # If we don't know the hash or a path with that hash doesn't exist,
 # download the file and add it to the store.
 if [[ -z "$finalPath" ]]; then
-
     # nix>=2.20 rejects adding symlinked paths to the store, so use realpath
     # to resolve to a physical path. https://github.com/NixOS/nix/issues/11941
-    tmpPath="$(realpath "$(mktemp -d "${TMPDIR:-/tmp}/hg-checkout-tmp-XXXXXXXX")")"
+    tmpPath="$(realpath "$(mktemp -d --tmpdir hg-checkout-tmp-XXXXXXXX)")"
     cleanup() { x=$?; rm -rf "$tmpPath"; exit $x; }; trap cleanup EXIT
 
     tmpArchive="$tmpPath/hg-archive"

pkgs/build-support/fetchsvn/nix-prefetch-svn

···
 if test -z "$finalPath"; then
     # nix>=2.20 rejects adding symlinked paths to the store, so use realpath
     # to resolve to a physical path. https://github.com/NixOS/nix/issues/11941
-    tmpPath="$(realpath "$(mktemp -d "${TMPDIR:-/tmp}/svn-checkout-tmp-XXXXXXXX")")"
+    tmpPath="$(realpath "$(mktemp -d --tmpdir svn-checkout-tmp-XXXXXXXX)")"
     trap "rm -rf \"$tmpPath\"" EXIT
 
     tmpFile="$tmpPath/$dstFile"

pkgs/tools/package-management/nix-prefetch-scripts/default.nix

···
     installPhase = ''
       install -vD ${src} $out/bin/$name;
       wrapProgram $out/bin/$name \
-        --prefix PATH : ${lib.makeBinPath (deps ++ [ gnused nix ])} \
+        --prefix PATH : ${lib.makeBinPath (deps ++ [ coreutils gnused nix ])} \
         --set HOME /homeless-shelter
     '';
 
···
 in rec {
   nix-prefetch-bzr = mkPrefetchScript "bzr" ../../../build-support/fetchbzr/nix-prefetch-bzr [ breezy ];
   nix-prefetch-cvs = mkPrefetchScript "cvs" ../../../build-support/fetchcvs/nix-prefetch-cvs [ cvs ];
-  nix-prefetch-git = mkPrefetchScript "git" ../../../build-support/fetchgit/nix-prefetch-git [ coreutils findutils gawk git git-lfs ];
+  nix-prefetch-git = mkPrefetchScript "git" ../../../build-support/fetchgit/nix-prefetch-git [ findutils gawk git git-lfs ];
   nix-prefetch-hg  = mkPrefetchScript "hg"  ../../../build-support/fetchhg/nix-prefetch-hg   [ mercurial ];
   nix-prefetch-svn = mkPrefetchScript "svn" ../../../build-support/fetchsvn/nix-prefetch-svn [ subversion ];