Merge branch 'jc/autogc' into js/rebase-i

* jc/autogc:
git-gc --auto: run "repack -A -d -l" as necessary.
git-gc --auto: restructure the way "repack" command line is built.
git-gc --auto: protect ourselves from accumulated cruft
git-gc --auto: add documentation.
git-gc --auto: move threshold check to need_to_gc() function.
repack -A -d: use --keep-unreachable when repacking
pack-objects --keep-unreachable
Export matches_pack_name() and fix its return value
Invoke "git gc --auto" from commit, merge, am and rebase.
Implement git gc --auto

Conflicts:

builtin-pack-objects.c

diff --cc Documentation/config.txt
Simple merge

diff --cc builtin-pack-objects.c
index a15906bdb2021e68a014344cad4e73e9de3367ca,ba7c8da5bf0b91c5ddab3fa692ca49d025d85e29..0be539ed7fd9bf95bb40515b560c7615ed318f37
--- 1/builtin-pack-objects.c
--- 2/builtin-pack-objects.c
+++ b/builtin-pack-objects.c
@@@ -24,8 -20,8 +24,8 @@@ git-pack-objects [{ -q | --progress | -
        [--max-pack-size=N] [--local] [--incremental] \n\
        [--window=N] [--window-memory=N] [--depth=N] \n\
        [--no-reuse-delta] [--no-reuse-object] [--delta-base-offset] \n\
 -      [--non-empty] [--revs [--unpacked | --all]*] [--reflog] \n\
 +      [--threads=N] [--non-empty] [--revs [--unpacked | --all]*] [--reflog] \n\
-       [--stdout | base-name] [<ref-list | <object-list]";
+       [--stdout | base-name] [--keep-unreachable] [<ref-list | <object-list]";
  
  struct object_entry {
        struct pack_idx_entry idx;

diff --cc cache.h
Simple merge

diff --cc git-am.sh
Simple merge

diff --cc git-commit.sh
Simple merge

diff --cc git-merge.sh
Simple merge

diff --cc git-rebase--interactive.sh
Simple merge

diff --cc git-repack.sh
index 0aae1a3ed5571a010f80438f8e8a0fc7eb0dc285,633b902e26a7e527c7a80ccf6aed2da5e71fa802..e72adc4d91efb8eb6dc96c1f431c8863c408439b
--- 1/git-repack.sh
--- 2/git-repack.sh
+++ b/git-repack.sh
@@@ -7,9 -7,9 +7,9 @@@ USAGE='[-a|-A] [-d] [-f] [-l] [-n] [-q
  SUBDIRECTORY_OK='Yes'
  . git-sh-setup
  
- no_update_info= all_into_one= remove_redundant=
+ no_update_info= all_into_one= remove_redundant= keep_unreachable=
  local= quiet= no_reuse= extra=
 -while case "$#" in 0) break ;; esac
 +while test $# != 0
  do
        case "$1" in
        -n)     no_update_info=t ;;