Document building with distcc in tutorial, add it to RELEASE_NOTES and CHANGES.html.

CHANGES.html

@@ -69,7 +69,7 @@ A user can call these functions to set/get the corresponding socket option. See
 
 <h2>Changes to build system:</h2>
 <ul>
-<li></li>
+<li>It's now possible to use distcc when building ns-3. See tutorial for details.</li>
 </ul>
 
 <h2>Changed behavior:</h2>

RELEASE_NOTES

@@ -21,8 +21,13 @@ Supported platforms
 
 New user-visible features
 -------------------------
--Support several new LTE MAC schedulers developed in GSoC 2012 project. Those schedulers include FD-MT, TD-MT, TTA, FD-BET, TD-BET, FD-TBFQ, TD-TBFQ, PSS. Here, FD and TD mean frequency domain and time domain respectively.
-
+- Support several new LTE MAC schedulers developed in GSoC 2012 project. 
+  Those schedulers include FD-MT, TD-MT, TTA, FD-BET, TD-BET, FD-TBFQ,
+  TD-TBFQ, PSS. Here, FD and TD mean frequency domain and time domain 
+  respectively.
+- It's now possible to use distcc when building ns-3 by using
+  $ CXX='distcc g++' ./waf configure
+  $ ./waf build
 
 Bugs fixed
 ----------

doc/tutorial/source/getting-started.rst

@@ -471,6 +471,28 @@ the ``-o`` option to configure; e.g.
 This allows users to work with multiple builds rather than always
 overwriting the last build.
 
+In the examples above, waf uses GCC C++ compiler, command ``g++``, for
+building ns-3. However, it's possible to change C++ compiler used by waf.
+Say one wants to use Clang C++ compiler, command ``clang++``; it's done by
+
+::
+
+  CXX="clang++" ./waf configure
+  ./waf build
+
+One can also set up waf to do distributed compilation with ``distcc`` in
+a similar way:
+
+::
+
+  CXX="distcc g++" ./waf configure
+  ./waf build
+
+More info on distcc and distributed compilation can be found on it's
+`project page
+<http://code.google.com/p/distcc/>`_
+under Documentation section.
+
 Testing ns-3
 ************