Publish a tarball containing the crates we depend on

This is needed since we no longer produce a source tarball.

(cherry picked from commit bf70a047a0)

release.nix

@@ -12,11 +12,9 @@ let
     builtins.readFile ./.version
     + (if officialRelease then "" else "pre${toString nix.revCount}_${nix.shortRev}");
 
-  jobs = rec {
-
   # Create a "vendor" directory that contains the crates listed in
   # Cargo.lock. This allows Nix to be built without network access.
-    vendoredCrates =
+  vendoredCrates' =
     let
       lockFile = builtins.fromTOML (builtins.readFile nix-rust/Cargo.lock);
 
@@ -57,6 +55,20 @@ let
         '') files)}
       '';
 
+  jobs = rec {
+
+    vendoredCrates =
+      with pkgs;
+      runCommand "vendored-crates" {}
+        ''
+          mkdir -p $out/nix-support
+          name=nix-vendored-crates-${version}
+          fn=$out/$name.tar.xz
+            tar cvfJ $fn -C ${vendoredCrates'} vendor \
+              --owner=0 --group=0 --mode=u+rw,uga+r \
+              --transform "s,vendor,$name,"
+            echo "file crates-tarball $fn" >> $out/nix-support/hydra-build-products
+        '';
 
     build = pkgs.lib.genAttrs systems (system:
 
@@ -89,7 +101,7 @@ let
               patchelf --set-rpath $out/lib:${stdenv.cc.cc.lib}/lib $out/lib/libboost_thread.so.*
             ''}
 
-            ln -sfn ${vendoredCrates}/vendor/ nix-rust/vendor
+            ln -sfn ${vendoredCrates'}/vendor/ nix-rust/vendor
 
             (cd perl; autoreconf --install --force --verbose)
           '';