see if sanitizers work across the board

[dpo]

Sanitizers are tools that can help diagnose memory, addressing, and other types of errors. See https://github.com/google/sanitizers.

[dpo]

@nimgould In this pull request, I build GALAHAD with sanitizers enabled. They are alternatives to Valgrind to diagnose various types of issues. We see issues on both Linux and macOS. They are not very verbose, but perhaps you will see more output if you try locally. The only difference is that you set up the build dir with the command

meson setup -Db_sanitize=address,undefined builddir

then you run the unit tests normally, all at once or one at a time.

On my ARM64 Mac, one of those sanitizers suggested a possible cause for the gltrt failure in single precision. After investigating, I realized that GLTR_ttrs was called with n = 0. That is because dim_sub = 0 earlier, but I haven't yet determined the cause of that. I suspect integer size mismatches (especially when we call BLAS/LAPACK), but it seems there may also be buffer overruns/leaks/etc.

[amontoison]

Thanks @dpo! We added it on master.