[Boost-build] Added a new version.check-jam-version rule.

From: Jurko Gospodnetiæ (jurko.gospodnetic_at_[hidden])
Date: 2008-05-03 19:36:27

   Hi all.

   Just added functionality for more easily testing the Boost Jam 
version from Jamfiles.

   Now you can use the version.check-jam-version rule, as in [ 
versions.check-jam-version 3 1 17 ] which will return true if the 
current Boost Jam version is at least 3.1.17. Also takes care of all the 
problems with versions sometimes being returned with leading zeroes.

   Related internal Boost Build tests included.

   Changeset link: http://svn.boost.org/trac/boost/changeset/45096

   Hope this helps someone.

   Best regards,
     Jurko Gospodnetiæ