Build stage by default and explain where the libraries are put.

[SVN r52322]

Jamroot

@@ -582,6 +582,26 @@ targets.create-metatarget top-level-target : [ project.current ]
 explicit install ;
 explicit stage ;
 
+stage-abs = [ path.native [ path.root $(stage-locate)/lib [ path.pwd ] ] ] ;
+
+# This target is built by default, and will forward to 'stage'
+# after producing some explanations.
+alias forward : explain stage ;
+message explain :
+"\nBuilding C++ Boost.
+
+After the build, the headers will be located at
+  
+  $(BOOST_ROOT)
+    
+The libraries will be located at  
+    
+   $(stage-abs)
+     
+Use 'bjam install --prefix=<path>' if you wish to install headers and 
+libraries to a different location and remove the source tree.\n\n"
+  ;
+
 
 # Just build the libraries, don't install them anywhere. This is what happens
 # with just "bjam --v2".