macOS now uses SecRandomCopyBytes for us

[RalfJung]

This builds on top of rust-lang/rust#60156.

Fixes #686

[RalfJung]

Uh, dang. Maybe that was not such a good idea:

  = note: Undefined symbols for architecture x86_64:
            "_SecRandomCopyBytes", referenced from:
                std::sys::unix::rand::hashmap_random_keys::hbdc7ddba9ddf117d in std.std.8sfdv10m-cgu.6.rcgu.o
          ld: symbol(s) not found for architecture x86_64
          clang: error: linker command failed with exit code 1 (use -v to see invocation)

@ebarnard had the same problem with rust-lang/rust#59879, I wonder if we can apply their solution conditionally. They added cargo:rustc-link-lib=framework=Security to the build script output; can that depend on features?

[oli-obk]

can that depend on features?

You should be able to use CARGO_CFG_<cfg> according to the docs https://doc.rust-lang.org/cargo/reference/environment-variables.html#environment-variables-cargo-sets-for-build-scripts

[RalfJung]

This is not a "configuration option" of libstd though, it's a --cfg miri passed via RUSTFLAGS.