submodules: load gitmodules file from commit sha1

teach submodules to load a '.gitmodules' file from a commit sha1.  This
enables the population of the submodule_cache to be based on the state
of the '.gitmodules' file from a particular commit.

Signed-off-by: Brandon Williams <bmwill@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/cache.h b/cache.h
index e12a5d912..de237cab6 100644
--- a/cache.h
+++ b/cache.h
@@ -1693,6 +1693,8 @@ extern int git_default_config(const char *, const char *, void *);
 extern int git_config_from_file(config_fn_t fn, const char *, void *);
 extern int git_config_from_mem(config_fn_t fn, const enum config_origin_type,
 					const char *name, const char *buf, size_t len, void *data);
+extern int git_config_from_blob_sha1(config_fn_t fn, const char *name,
+				     const unsigned char *sha1, void *data);
 extern void git_config_push_parameter(const char *text);
 extern int git_config_from_parameters(config_fn_t fn, void *data);
 extern void git_config(config_fn_t fn, void *);