Cargo is always pass " -c prefer-dynamic" and linking std dynamically if one of the dependency is "dylib". Can it be linked statically?
Are you making a portable library? If so, then you need cdyilb type and export a C API.
dylib is for Rust libs, which don't have a stable ABI, so dependence on libstd is the least of their problems 
No, i not making a portable library. I split my main app with one nested crate which type i make dylib for optimize final compile and link time. But then all my app have std linked dynamically. Can it be linked staticaly?