sparse-index: add index.sparse config option

When enabled, this config option signals that index writes should
attempt to use sparse-directory entries.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/cache.h b/cache.h
index 74b43aa..8aede37 100644
--- a/cache.h
+++ b/cache.h
@@ -1059,6 +1059,7 @@ struct repository_format {
 	int worktree_config;
 	int is_bare;
 	int hash_algo;
+	int sparse_index;
 	char *work_tree;
 	struct string_list unknown_extensions;
 	struct string_list v1_only_extensions;