add stuff about debug build.

foocanvas/foocanvas_build.html

-<!-- CVS info:   $Id: foocanvas_build.html,v 1.4 2010-03-23 14:44:39 edgrif Exp $ -->
+<!-- CVS info:   $Id: foocanvas_build.html,v 1.5 2010-03-24 11:24:02 edgrif Exp $ -->
 
 
 
@@ -434,6 +434,21 @@ the preceding section and do the following:</p>
 </pre>
 
 
+<p>To build a debug version of the canvas and install it locally:</p>
+
+<pre>
+
+> ./configure --prefix=&lt;your local directory&gt; CFLAGS=-g
+
+> make
+
+> make install
+
+</pre>
+
+
+
+
 <a name="appendix">
 <h2>Appendix</h2>
 </a>