Add the closure of store paths to the chroot

Thus, for example, to get /bin/sh in a chroot, you only need to
specify /bin/sh=${pkgs.bash}/bin/sh in build-chroot-dirs. The
dependencies of sh will be added automatically.

release.nix

@@ -95,11 +95,10 @@ let
 
         # Provide a default value for the ‘build-chroot-dirs’ setting
         # that includes /bin/sh pointing to bash.
-        preHook = lib.optionalString stdenv.isLinux (
-          let sh = stdenv.shell; in
+        preHook = lib.optionalString stdenv.isLinux
           ''
-            export DEFAULT_CHROOT_DIRS="/bin/sh=${sh} $(tr '\n' ' ' < ${writeReferencesToFile sh})"
-          '');
+            export DEFAULT_CHROOT_DIRS="/bin/sh=${stdenv.shell}"
+          '';
 
         enableParallelBuilding = true;
 

src/libstore/build.cc

@@ -1799,6 +1799,14 @@ void DerivationGoal::startBuilder()
         }
         dirsInChroot[tmpDir] = tmpDir;
 
+        /* Add the closure of store paths to the chroot. */
+        PathSet closure;
+        for (auto & i : dirsInChroot)
+            if (isInStore(i.second))
+                computeFSClosure(worker.store, toStorePath(i.second), closure);
+        for (auto & i : closure)
+            dirsInChroot[i] = i;
+
         string allowed = settings.get("allowed-impure-host-deps", string(DEFAULT_ALLOWED_IMPURE_PREFIXES));
         PathSet allowedPaths = tokenizeString<StringSet>(allowed);