Describe the bug

I understand that purely static binaries are not supported under Darwin, due to the unstable system call ABI. My suggestion is that pkgsStatic, on Darwin or cross-compiling to Darwin, should produce static libraries, which would result in dynamic binaries which only depend on libSystem.dylib. This would be useful for single-file software for embedding, as well as simplifying distribution of Nix-built binaries on systems without Nix.

Steps To Reproduce

Steps to reproduce the behavior:

1. Build nixpkgs#legacyPackages.x86_64-darwin.pkgsStatic.nix
2. Run llvm-otool -L result/bin/nix
3. Resulting derivation is a dynamic executable with dependencies elsewhere in the Nix Store

Expected behavior

Resulting executable would only depend on /usr/lib/libSystem.B.dylib

Notify maintainers

@NixOS/darwin-maintainers