Merge branch 'jt/packmigrate' into next

Code movement to make it easier to hack later.

* jt/packmigrate: (23 commits)
pack: move for_each_packed_object()
pack: move has_pack_index()
pack: move has_sha1_pack()
pack: move find_pack_entry() and make it global
pack: move find_sha1_pack()
pack: move find_pack_entry_one(), is_pack_valid()
pack: move check_pack_index_ptr(), nth_packed_object_offset()
pack: move nth_packed_object_{sha1,oid}
pack: move clear_delta_base_cache(), packed_object_info(), unpack_entry()
pack: move unpack_object_header()
pack: move get_size_from_delta()
pack: move unpack_object_header_buffer()
pack: move {,re}prepare_packed_git and approximate_object_count
pack: move install_packed_git()
pack: move add_packed_git()
pack: move unuse_pack()
pack: move use_pack()
pack: move pack-closing functions
pack: move release_pack_memory()
pack: move open_pack_index(), parse_pack_index()
...

diff --cc builtin/fsck.c
Simple merge

diff --cc builtin/merge.c
Simple merge

diff --cc builtin/prune-packed.c
Simple merge

diff --cc cache.h
Simple merge

diff --cc diff.c
Simple merge

diff --cc http.c
Simple merge

diff --cc sha1_file.c
index 081820ac293a8fa9f0861ce1159ee73b0b45f5a1,bb0831b4c803919e90ce263c4aed31d7fedd4620..5f71bbac3ea9a11a4369ec0353e2e1258979ba19
--- 1/sha1_file.c
--- 2/sha1_file.c
+++ b/sha1_file.c
@@@ -28,11 -28,9 +28,9 @@@
  #include "list.h"
  #include "mergesort.h"
  #include "quote.h"
- 
- #define SZ_FMT PRIuMAX
- static inline uintmax_t sz_fmt(size_t s) { return s; }
+ #include "packfile.h"
  
 -const unsigned char null_sha1[20];
 +const unsigned char null_sha1[GIT_MAX_RAWSZ];
  const struct object_id null_oid;
  const struct object_id empty_tree_oid = {
        EMPTY_TREE_SHA1_BIN_LITERAL