Fortran-stdlib: v0.6.0

[zoziha]

Description

Fortran-stdlib comes with modern Reference-BLAS built into v0.6.0, and also provides macro definitions to use external BLAS and LAPACK.
This PR upgrades Fortran-stdlib to v0.6.0 and links to OpenBLAS for optimized performance by adding a CMake patch.

[Biswa96]

Did you try to upstream the patch?

[zoziha]

Fortran-stdlib does not address enabling OpenBLAS or other implementations in CMake yet. Current focus is to implement linear algebra subroutines, that will come next.

Fortran-stdlib requires reasonable references to external BLAS libraries from complex sources (e.g. intel MKL, OpenBLAS, etc.), which requires a long implementation plan. Since the OpenBLAS package is included in MSYS2, my simple idea is to take advantage of it directly to get optimized performance, and I will continue to follow the progress of Fortran-stdlib.

@Biswa96, if you think it's not appropriate to add a CMake patch for Fortran-stdlib to MSYS2 at this stage, I'll remove the CMake linking OpenBLAS patch for Fortran-stdlib and revert to updating only the Fortran-stdlib version.

[Biswa96]

In general, I prefer to upstream any significant changes first. I am not familiar with this project. Although I would welcome any change to improve performance. Please wait for other to comment on this PR.