hpl's Makefile used ARCH for some own things which conflicted with the predefined ARCH. I renamed hpl's ARCH variable.
- needs an MPI implementation (mpich and lam are supported by this port) - needs an Basic Linear Algebra Subprograms implementation like atlas (default) or blas (both are supported by this port) tested on alpha (5), amd64 (5) and i386 (4 and 5)