Add program options to the main Jamfile.v2.

[SVN r22857]

Jamfile.v2

@@ -26,4 +26,4 @@ build-project libs/graph/build ;
 build-project libs/python/build ;
 build-project libs/thread/build ;
 build-project libs/filesystem/build ;
-
+build-project libs/program_options/build ;