lib/deltas: Port to more to new code style

Looking at the uses of `ostree_repo_load_file()` here.

Closes: #953
Approved by: jlebon

src/libostree/ostree-rollsum.h

@@ -21,6 +21,7 @@
 #pragma once
 
 #include <gio/gio.h>
+#include "libglnx.h"
 
 G_BEGIN_DECLS
 
@@ -39,5 +40,6 @@ _ostree_compute_rollsum_matches (GBytes                           *from,
                                  GBytes                           *to);
 
 void _ostree_rollsum_matches_free (OstreeRollsumMatches *rollsum);
+G_DEFINE_AUTOPTR_CLEANUP_FUNC(OstreeRollsumMatches, _ostree_rollsum_matches_free)
 
 G_END_DECLS