New BLAS/LAPACK system

[Jason Bacon <outpaddling%yahoo.com@localhost>]

To anyone maintaining BLAS/LAPACK-dependent packages:

We have a new system in-place, developed by Thomas Orgis, that allows 
pkgsrc packages to use any BLAS/LAPACK implementation without 
modification to the package.

This system will greatly improve the usability of pkgsrc in science by 
providing flexibility and the superior performance of alternative 
implementations such as OpenBLAS.

Key points:

- Any pkgsrc package using BLAS/LAPACK should now use

.include "../../mk/blas.buildlink3.mk"

rather than bl3s from individual packages such as math/blas or 
math/lapack.  mk/blas.buildlink3.mk will provide both BLAS and LAPACK 
libraries to all packages.  Most implementations use a single library 
now and even the netlib blas package is little more than a placeholder 
for backward compatibility.

- Currently supported implementations include Netlib BLAS/LAPACK (the 
only implementation provided by pkgsrc until now), OpenBLAS 
single-threaded, pthreads, or openmp (currently in WIP, to be committed 
soon), and Apple's Accelerate.framework.  Netlib is the default since it 
is the reference implementation.

- As of this moment, only Netlib packages are committed.  OpenBLAS, 
cblas, and lapacke are basically finished, currently available in wip, 
and will be committed soon.

- Pkgsrc users can select one or more BLAS implementations by simply 
setting PKGSRC_BLAS_TYPES in etc/mk.conf.

- It is still possible to include package bl3s directly, but this is 
strongly discouraged.  If for some reason a maintainer needs to restrict 
a package to one or more particular implementations, this can be done by 
setting BLAS_ACCEPTED in the package Makefile.

- See the comments in mk/blas.buildlink3.mk for details.

All existing dependent packages have been updated and revbumped to use 
the new system.

Please post any questions or suggestions to this group.

Enjoy!