[gtk-doc] docs: add info for creating better tarballs

[Stefan Kost <stefkost src gnome org>]

commit c58b07111a87de03f2be9b1215883c6f71133989
Author: Stefan Sauer <ensonic users sf net>
Date:   Wed Jul 9 15:21:31 2014 +0200

    docs: add info for creating better tarballs

 HACKING |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/HACKING b/HACKING
index 0f0f401..7512718 100644
--- a/HACKING
+++ b/HACKING
@@ -28,7 +28,7 @@ http://live.gnome.org/MaintainersCorner/Releasing
   git push
 
 - dist
-  make distcheck
+   TAR_OPTIONS="--owner=root --group=root" make distcheck
 
 - tag
   git tag -a GTK_DOC_1_12 -m"release: 1.12"