Merge branch 'jc/attr-source-tree'

"git --attr-source=<tree> cmd $args" is a new way to have any
command to read attributes not from the working tree but from the
given tree object.

* jc/attr-source-tree:
  attr: teach "--attr-source=<tree>" global option to "git"

diff --cc Documentation/git.txt
Simple merge

diff --cc archive.c
Simple merge

diff --cc attr.c
index ddf2b0cbc2ec8e0deac3b03cbfffae84af0a075a,11238d6083d4ae7eb710d72b9a720bc04d4eb462..d45d34058df639c9a6c3fc80f51fa864611e5b21
--- 1/attr.c
--- 2/attr.c
+++ b/attr.c
@@@ -20,7 -20,7 +20,8 @@@
  #include "object-store.h"
  #include "setup.h"
  #include "thread-utils.h"
 +#include "tree-walk.h"
+ #include "object-name.h"
  
  const char git_attr__true[] = "(builtin)true";
  const char git_attr__false[] = "\0(builtin)false";

diff --cc builtin/check-attr.c
Simple merge

diff --cc convert.c
Simple merge

diff --cc ll-merge.c
Simple merge

diff --cc pathspec.c
Simple merge

diff --cc ws.c
Simple merge