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
