Merge branch 'jc/cache-tree' into next

* jc/cache-tree:
commit-tree: allow generic object name for the tree as well.
Makefile: remove and create xdiff library from scratch.
t0000-basic: Add ls-tree recursive test back.

diff --cc Makefile
Simple merge

diff --cc update-index.c
index 157488ff1a87df262e6177671f5e568b8d155de3,258a88cbeac7edc103b94446198383628c2e19cb..4c6bcfaedd6cd6bb53c0d783ef49fcd24b191850
--- 1/update-index.c
--- 2/update-index.c
+++ b/update-index.c
@@@ -6,8 -6,8 +6,9 @@@
  #include "cache.h"
  #include "strbuf.h"
  #include "quote.h"
+ #include "cache-tree.h"
  #include "tree-walk.h"
 +#include "cache-tree.h"
  
  /*
   * Default to not allowing changes to the list of files. The