Adjust doc build to avoid boost-root references.

Author: grafikrobot

doc/Jamfile.v2

@@ -2,15 +2,15 @@
 import toolset ;
 toolset.using doxygen ;
 
-boostbook program_option 
-    : program_options.xml 
-    : <implicit-dependency>autodoc 
+boostbook program_option
+    : program_options.xml
+    : <implicit-dependency>autodoc
       <xsl:param>boost.root=../../../..
       <format>pdf:<xsl:param>boost.url.prefix=http://www.boost.org/doc/libs/release/doc/html
     ;
 
-doxygen autodoc 
-    : [ glob ../../../boost/program_options/*.hpp ] ;
+doxygen autodoc
+    : [ glob ../include/boost/program_options/*.hpp ] ;
 
 ###############################################################################
 alias boostdoc