diff.h: reduce unnecessary includes

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

attr.c

@@ -20,6 +20,7 @@
 #include "object-store.h"
 #include "setup.h"
 #include "thread-utils.h"
+#include "tree-walk.h"
 
 const char git_attr__true[] = "(builtin)true";
 const char git_attr__false[] = "\0(builtin)false";

diff.h

@@ -4,7 +4,6 @@
 #ifndef DIFF_H
 #define DIFF_H
 
-#include "tree-walk.h"
 #include "pathspec.h"
 #include "oidset.h"
 #include "strbuf.h"

http-push.c

@@ -16,6 +16,7 @@
 #include "sigchain.h"
 #include "strvec.h"
 #include "tree.h"
+#include "tree-walk.h"
 #include "packfile.h"
 #include "object-store.h"
 #include "commit-reach.h"

line-log.c

@@ -18,6 +18,7 @@
 #include "setup.h"
 #include "strvec.h"
 #include "bloom.h"
+#include "tree-walk.h"
 
 static void range_set_grow(struct range_set *rs, size_t extra)
 {

pack-bitmap-write.c

@@ -19,6 +19,7 @@
 #include "prio-queue.h"
 #include "trace2.h"
 #include "tree.h"
+#include "tree-walk.h"
 
 struct bitmapped_commit {
 	struct commit *commit;

reflog.c

@@ -5,6 +5,7 @@
 #include "refs.h"
 #include "revision.h"
 #include "tree.h"
+#include "tree-walk.h"
 #include "worktree.h"
 
 /* Remember to update object flag allocation in object.h */

tree-diff.c

@@ -5,6 +5,7 @@
 #include "diff.h"
 #include "diffcore.h"
 #include "tree.h"
+#include "tree-walk.h"
 
 /*
  * Some mode bits are also used internally for computations.