Tweak exception testing dependency to only header only use.

build.jam

@@ -11,7 +11,7 @@ project /boost/leaf
     ;
 
 explicit
-    [ alias boost_leaf : : : : <library>$(boost_dependencies) ]
+    [ alias boost_leaf ]
     [ alias all : boost_leaf test ]
     ;
 

test/Jamfile.v2

@@ -23,7 +23,7 @@ project
         <threading>multi
     : requirements
         <library>/boost/config//boost_config
-        <library>/boost/exception//boost_exception
+        <use>/boost/exception//boost_exception
         <define>BOOST_LEAF_BOOST_AVAILABLE
         <target-os>windows:<define>_CRT_SECURE_NO_WARNINGS
         <threading>single:<define>BOOST_LEAF_NO_THREADS