1.  The default c++ compiler for OS X 10.7 is actually clang (``/usr/bin/c++``).

    Using clang exposes invalid template code. The first of many errors is::

      In file included from

      /opt/cctbx/cctbx_sources/mmtbx/bulk_solvent/bulk_solvent_ext.cpp:7:

       /opt/cctbx/cctbx_sources/mmtbx/bulk_solvent/bulk_solvent.h:496:21:

      error: call to function 'r_factor' that is neither visible in the template

        definition nor found by argument-dependent lookup

            r.push_back(r_factor(f_obs, f_model.const_ref()));