Merge branch 'dh/repack' (early part)

* 'dh/repack' (early part):
  Ensure git-repack -a -d --max-pack-size=N deletes correct packs
  pack-objects: clarification & option checks for --max-pack-size
  git-repack --max-pack-size: add option parsing to enable feature
  git-repack --max-pack-size: split packs as asked by write_{object,one}()
  git-repack --max-pack-size: write_{object,one}() respect pack limit
  git-repack --max-pack-size: new file statics and code restructuring
  Alter sha1close() 3rd argument to request flush only

Documentation/git-pack-objects.txt

@@ -85,6 +85,11 @@ base-name::
 	times to get to the necessary object.
 	The default value for --window is 10 and --depth is 50.
 
+--max-pack-size=<n>::
+	Maximum size of each output packfile, expressed in MiB.
+	If specified,  multiple packfiles may be created.
+	The default is unlimited.
+
 --incremental::
 	This flag causes an object already in a pack ignored
 	even if it appears in the standard input.

Documentation/git-repack.txt

@@ -65,6 +65,11 @@ OPTIONS
 	to be applied that many times to get to the necessary object.
 	The default value for --window is 10 and --depth is 50.
 
+--max-pack-size=<n>::
+	Maximum size of each output packfile, expressed in MiB.
+	If specified,  multiple packfiles may be created.
+	The default is unlimited.
+
 
 Configuration
 -------------