Bug#961186: scalapack: provide a 64-bit build

[Drew Parsons]

Source: scalapack
Followup-For: Bug #961186

64 bit support now added upstream (git not yet released),
-fdefault-integer-8 (perhaps also -DInt=long ?) with 64-bit BLAS.

https://github.com/Reference-ScaLAPACK/scalapack/commit/8ab1b6ed1ed7630a4c166d548fd7a3bc62784bb2
https://github.com/Reference-ScaLAPACK/scalapack/commit/0a00a099082d775c0f75cfcf255cfddbb119ad2a

https://github.com/Reference-ScaLAPACK/scalapack/pull/19