use the correct liblapack name

[KristofferC]

We got reports of users segfaulting when BLAS functions in this module was called. This was debugged down into an inconsistency between Base.liblapack_name and LinearAlgebra.LAPACK.liblapack. The correct one to use is the latter and with that change the segfaults disappeared. Also note that the former might be removed (JuliaLang/julia#50699).

As a side note, some of the functions provided here are now available in LinearAlgebra itself, see for example JuliaLang/julia#32390.

[andreasvarga]

We got reports of users segfaulting when BLAS functions in this module was called.

Could you provide a link to this problematic? Are these segfaults occuring with OpenBLAS or with MKL?

I already planned a version bump to replace

Base.liblapack_name
with

@static if VERSION < v"1.7"
    using LinearAlgebra.LAPACK: liblapack
elseif VERSION < v"1.9"
    const liblapack = "libblastrampoline"
else
    const liblapack = LinearAlgebra.libblastrampoline
end

(see the discussion here).

Although I can fix the MKL compliance issue myself for MatrixPencils (by replacing some wrappers with Julia implementations of the same LAPACK codes), I decided to wait with the version bump until this PR will be merged.

[KristofferC]

Could you provide a link to this problematic?

This was from a support issue with a customer. The issue they had was that they had managed to get rid of the symlinks between libtrampoline.so and libtrampoline.so.5. This means that the discrepancy between Base.liblapack_name and LinearAlgebra.LAPACK.liblapack caused that calling into MatrixPencils.jl would use a separate (but identical) library but this library would not have been initialized so any use of it would segfault.

So in some sense, this is right now only a problem in combination with another issue, but nonetheless I would say the behavior in here is more correct and since Base.lilbapack_name might go away, this is probably a good idea anyway.

[andreasvarga]

Should I go forward with my proposal or would you like a modified one?

[KristofferC]

I think your suggestion is fine.

[andreasvarga]

OK, I will make a new release and also enforce MKL compatibility.