Merge staging-next into staging

pkgs/build-support/docker/default.nix

@@ -770,6 +770,7 @@ rec {
           mkdir $out
 
           tar \
+            --sort name \
             --owner 0 --group 0 --mtime "@$SOURCE_DATE_EPOCH" \
             --hard-dereference \
             -C old_out \

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

@@ -105,7 +105,7 @@ fi
 
 init_remote(){
     local url=$1
-    clean_git init
+    clean_git init --initial-branch=master
     clean_git remote add origin "$url"
     ( [ -n "$http_proxy" ] && clean_git config http.proxy "$http_proxy" ) || true
 }