I just merged some GSoC work into Boost.uBLAS. This contains two Boost.Build "extension modules" ("opencl.jam" and "clblas.jam"), which are used in Jamfiles ("using clblas ;", for example in https://github.com/boostorg/ublas/blob/develop/test/opencl/Jamfile).

What is the proper way to

* point `b2` to  find these modules ? (I can of course set BOOST_BUILD_PATH, but I find that not very scalable. Should I ask all Boost users & testers to do that ? Isn't there a way to set this programmatically, from within the project's Jamfile ?)

* add a way to deal with the case where the modules aren't found. Right now `./b2` will abort with an error. I'd prefer to print a warning and then skip the parts that require it.



      ...ich hab' noch einen Koffer in Berlin...