Require a compiler which does not need BOOST_NO_EXPLICIT_FUNCTION_TEMPLATE_ARGUMENTS
This was defined independent of the compiler version. It is not known
if this is a true limitation of the digital mars compiler in all
versions, or a bug in this header.
(from Stephen Kelly)
Daniel James: I checked the latest version of digital mars. It mostly supports
explicit function template arguments, apart when a function is overloaded for
type and value template arguments, which causes the config test to fail. So in
most cases the macro isn't needed.