config_file: make use of `GIT_CONTAINER_OF` macro
diff --git a/src/config_file.c b/src/config_file.c
index 26c9e5e..a305021 100644
--- a/src/config_file.c
+++ b/src/config_file.c
@@ -227,9 +227,9 @@ static void backend_free(git_config_backend *_backend)
static int config_iterator_new(
git_config_iterator **iter,
- struct git_config_backend* backend)
+ struct git_config_backend *backend)
{
- diskfile_header *bh = (diskfile_header *) backend;
+ diskfile_header *bh = GIT_CONTAINER_OF(backend, diskfile_header, parent);
git_config_entries *entries;
int error;