[gtk+/composite-templates] Update installation instructions for 3.6

[Juan Pablo Ugarte <jpu src gnome org>]

commit fb46586ea87caf7b1ba57b8e3f4bbf4914ee834d
Author: Matthias Clasen <mclasen redhat com>
Date:   Mon Sep 24 18:53:03 2012 -0400

    Update installation instructions for 3.6

 INSTALL.in |   10 +++++-----
 1 files changed, 5 insertions(+), 5 deletions(-)
---
diff --git a/INSTALL.in b/INSTALL.in
index c18b995..c0b84f2 100644
--- a/INSTALL.in
+++ b/INSTALL.in
@@ -18,12 +18,12 @@ GTK+ requires the following packages:
 Simple install procedure
 ========================
 
-  % gzip -cd gtk+- GTK_VERSION@.tar.gz | tar xvf - # unpack the sources
-  % cd gtk+- GTK_VERSION@                          # change to the toplevel directory
-  % ./configure                                    # run the `configure' script
-  % make                                           # build GTK+
+  % tar xf gtk+- GTK_VERSION@.tar.xz   # unpack the sources
+  % cd gtk+- GTK_VERSION@              # change to the toplevel directory
+  % ./configure                        # run the `configure' script
+  % make                               # build GTK+
   [ Become root if necessary ]
-  % make install                                   # install GTK+
+  % make install                       # install GTK+
 
 The Details
 ===========