Needed to build an executable that uses OpenMP with clang. This
includes a header file and a library that clang will link into an
executable whose source makes use of ‘omp‘ pragmas.
This reflects upstream versioning change, and allows
us to replace 4.0 with 4.1 (which is now a minor revision)
without changing the attribute name.
Thanks to @vcunat for the idea.
Anthony Cowley
Dan Peebles
Will Dietz