Restore dont-download-stage0 patch to build the orig-dl tarball with the hashes

debian/TODO.Debian

@@ -1,6 +1,5 @@
 For 1.15.1:
 
- * Check that build with bundled dl/ doesn't try to download the checksums again
  * See if we can go back to debhelper compat 9 as that makes backporting easier
  * B-D binutils-multiarch -> binutils since upstream no longer do that in the tests
 

debian/patches/d-dont-download-stage0.patch

@@ -0,0 +1,50 @@
+Description: Don't download SHA256 if it's already available locally
+ In Debian we provide the stage0 tarballs as a separate component so that the
+ buildds don't need to access the network during the build.
+Author: Ximin Luo <infinity0@debian.org>
+Forwarded: not-needed
+---
+This patch header follows DEP-3: http://dep.debian.net/deps/dep3/
+--- a/src/bootstrap/bootstrap.py
++++ b/src/bootstrap/bootstrap.py
+@@ -22,15 +22,17 @@
+ from time import time
+ 
+ 
+-def get(url, path, verbose=False):
++def get(url, path, verbose=False, use_local_hash_if_present=False):
+     sha_url = url + ".sha256"
+     with tempfile.NamedTemporaryFile(delete=False) as temp_file:
+         temp_path = temp_file.name
+-    with tempfile.NamedTemporaryFile(suffix=".sha256", delete=False) as sha_file:
+-        sha_path = sha_file.name
++    sha_path = path + ".sha256"
+ 
+     try:
+-        download(sha_path, sha_url, False, verbose)
++        if use_local_hash_if_present and os.path.exists(sha_path):
++            print("using already-download file " + sha_path)
++        else:
++            download(sha_path, sha_url, False, verbose)
+         if os.path.exists(path):
+             if verify(path, sha_path, False):
+                 if verbose:
+@@ -47,7 +49,6 @@
+             print("moving {} to {}".format(temp_path, path))
+         shutil.move(temp_path, path)
+     finally:
+-        delete_if_present(sha_path, verbose)
+         delete_if_present(temp_path, verbose)
+ 
+ 
+--- a/src/etc/get-stage0.py
++++ b/src/etc/get-stage0.py
+@@ -31,7 +31,7 @@
+     filename = 'rustc-{}-{}.tar.gz'.format(channel, triple)
+     url = 'https://static.rust-lang.org/dist/{}/{}'.format(date, filename)
+     dst = dl_dir + '/' + filename
+-    bootstrap.get(url, dst)
++    bootstrap.get(url, dst, use_local_hash_if_present=True)
+ 
+     stage0_dst = triple + '/stage0'
+     if os.path.exists(stage0_dst):

debian/patches/series

@@ -17,6 +17,7 @@ u-arm-on-64bit-kernel.diff
 d-rust-gdb-paths
 d-rust-lldb-paths
 d-add-soname.patch
+d-dont-download-stage0.patch
 d-fix-configure-for-deb-arches.patch
 d-dynamic-link-llvm.patch
 d-use-system-jquery.patch