Static linking libc++ clang

I trying to link statically the standard library libc++ (https://libcxx.llvm.org/) in Linux (Arch using this AUR https://aur.archlinux.org/packages/libc%2B%2B/) using Clang.

I get the error /usr/bin/ld: cannot find -lc++

The error is independent from the code, it appears even in a "Hello World".

If I remove the -static option it compiles (and links) and the generated executable works.

I don't want to use libstdc++ (I have my reasons not to please not focus the discussion in this) and the linking must be static (it's a requirement).

I'm perfectly aware that it's difficult to debug this stuff without having access to the machine where it happens. However, it happens it two different machines (both with Arch) so maybe it's something I'm forgetting about.

What I have tried so far is explained here (https://releases.llvm.org/7.0.0/projects/libcxx/docs/UsingLibcxx.html)

The basic command that shoud work it's the following clang++ -static -stdlib=libc++ -std=c++17 main.cpp -lc++abi