Add diff threading tests and attr file cache locks

This adds a basic test of doing simultaneous diffs on multiple
threads and adds basic locking for the attr file cache because
that was the immediate problem that arose from these tests.

1 files changed, 1 insertions, 0 deletions

diff --git a/src/attr_file.h b/src/attr_file.h
index 3bc7c6cb8..dbd6696c9 100644
--- a/src/attr_file.h
+++ b/src/attr_file.h
@@ -64,6 +64,7 @@ typedef struct {
 } git_attr_assignment;
 
 typedef struct {
+	git_refcount rc;
 	char *key;				/* cache "source#path" this was loaded from */
 	git_vector rules;		/* vector of <rule*> or <fnmatch*> */
 	git_pool *pool;