Merge branch 'np/pack'

* np/pack:
  add the capability for index-pack to read from a stream
  index-pack: compare only the first 20-bytes of the key.
  git-repack: repo.usedeltabaseoffset
  pack-objects: document --delta-base-offset option
  allow delta data reuse even if base object is a preferred base
  zap a debug remnant
  let the GIT native protocol use offsets to delta base when possible
  make pack data reuse compatible with both delta types
  make git-pack-objects able to create deltas with offset to base
  teach git-index-pack about deltas with offset to base
  teach git-unpack-objects about deltas with offset to base
  introduce delta objects with offset to base

git-repack.sh

@@ -3,7 +3,7 @@
 # Copyright (c) 2005 Linus Torvalds
 #
 
-USAGE='[-a] [-d] [-f] [-l] [-n] [-q]'
+USAGE='[-a] [-d] [-f] [-l] [-n] [-q] [--window=N] [--depth=N]'
 SUBDIRECTORY_OK='Yes'
 . git-sh-setup
 
@@ -25,6 +25,15 @@ do
 	shift
 done
 
+# Later we will default repack.UseDeltaBaseOffset to true
+default_dbo=false
+
+case "`git repo-config --bool repack.usedeltabaseoffset ||
+       echo $default_dbo`" in
+true)
+	extra="$extra --delta-base-offset" ;;
+esac
+
 PACKDIR="$GIT_OBJECT_DIRECTORY/pack"
 PACKTMP="$GIT_DIR/.tmp-$$-pack"
 rm -f "$PACKTMP"-*