Document the --non-empty command-line option to git-pack-objects.

This provides (minimal) documentation for the --non-empty command-line
option to the pack-objects command.
Signed-off-by: NNikolai Weibull <nikolai@bitwi.se>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

Documentation/git-pack-objects.txt

@@ -8,7 +8,7 @@ git-pack-objects - Create a packed archive of objects.
 
 SYNOPSIS
 --------
-'git-pack-objects' [--local] [--incremental] [--window=N] [--depth=N] {--stdout | base-name} < object-list
+'git-pack-objects' [--non-empty] [--local] [--incremental] [--window=N] [--depth=N] {--stdout | base-name} < object-list
 
 
 DESCRIPTION
@@ -70,6 +70,10 @@ base-name::
 	that are packed and not in the local object store
 	(i.e. borrowed from an alternate).
 
+--non-empty::
+        Only create a packed archive if it would contain at
+        least one object.
+
 Author
 ------
 Written by Linus Torvalds <torvalds@osdl.org>

pack-objects.c

@@ -4,7 +4,7 @@
 #include "pack.h"
 #include "csum-file.h"
 
-static const char pack_usage[] = "git-pack-objects [--local] [--incremental] [--window=N] [--depth=N] {--stdout | base-name} < object-list";
+static const char pack_usage[] = "git-pack-objects [--non-empty] [--local] [--incremental] [--window=N] [--depth=N] {--stdout | base-name} < object-list";
 
 struct object_entry {
 	unsigned char sha1[20];