Fix dependency on generated xinclude files.

doc/Jamfile.v2

@@ -190,9 +190,9 @@ boostbook doc
     src/boost.xml
     :
     <use>$(lib-doc-boostdoc-refs)
-    <use>libraries
+    <dependency>libraries
     <implicit-dependency>libraries
-    <use>tools
+    <dependency>tools
     <implicit-dependency>tools
 
     <dependency>images