Split brain: Actually generate .gitignore patch

Close our FH onto the file, and run git diff to fill it with the
actual diff.  Add the file to series.  Use git add and git commit to
commit the patch to the private git branch.

Now most of the code to generate the .gitignore properly is present, I
think, but not debugged.

1 files changed, 13 insertions, 2 deletions

diff --git a/dgit b/dgit
index 92f96ce..40c7f3e 100755
--- a/dgit
+++ b/dgit
@@ -2596,9 +2596,20 @@ updates to users of the official Debian archive view of the package.
 [dgit version $our_version]
 ---
 END
-    die 'xxx gitignore';
-	
+        close GIPATCH or die "$gipatch: $!";
+        runcmd shell_cmd "exec >>$gipatch", @git, qw(diff),
+            $unapplied, $headref, "--", keys %$editedignores;
+        open SERIES, "+>>", "debian/patches/series" or die $!;
+        defined seek SERIES, -1, 2 or $!==EINVAL or die $!;
+        my $newline;
+        defined read SERIES, $newline, 1 or die $!;
+	print SERIES "\n" or die $! unless $newline eq "\n";
+	print SERIES "auto-gitignore\n" or die $!;
+	close SERIES or die  $!;
+        runcmd @git, qw(add -- debian/patches/series), $gipatch;
+        commit_admin "Commit patch to update .gitignore";
     }
+
     die 'xxx memoisation via git-reflog';
     die 'xxx fast forward (should not depend on quilt mode, but will always be needed if we did $split_brain)';
 }