riscv64: ld.so hardware capabilities / V extension 1.0

[Mathieu Malaterre <malat@debian.org>]

Dear ld.so maintainers,

I see that from time to time subdirectories are added to the search
path of ld.so. For example I see that commit 45ff34638f0 added the
sub-directory `avx512_1`.

I tried to make sense of the (outdated?) documentation from:

* https://man7.org/linux/man-pages/man8/ld.so.8.html

but I failed to understand when new subdirectories are being added to ld.so ?

In my own very selfish interest I would like to request a new search
subdirectory for riscv64 with V-extensions. (-march=rv64gcv1p0), so I
would like to hear about this process.

Thanks,