WIP adding macos shared object

[alireza-nobakht]

Automate Rust FFI Build & Improve Cross-Platform Support

Summary

This PR adds a new script build_ffi.sh to automate:

• Cloning or updating the Rust repo valkey-glide
• Building the Rust FFI shared library (.so on Linux, .dylib on macOS) via cargo build --release
• Copying the compiled shared library into the Ruby gem’s lib/valkey folder

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Why?

The Rust shared library must be rebuilt and copied manually before, which is error-prone and tedious. This script simplifies and automates that, keeping the library up-to-date locally.

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Prerequisites

Rust toolchain (includes cargo)

Install via official Rust installer:

curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh
source $HOME/.cargo/env

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Protocol Buffers compiler (protoc)

Required by the Rust build process. On macOS, install with:

brew install protobuf

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How to run

From your valkey-glide-ruby gem root, run:

./build_ffi.sh

This will clone/update Rust repo, build the FFI shared library, and copy it to your gem folder.

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Important: Cargo.toml change needed

To support building a dynamic shared library for Ruby FFI, the Rust crate’s Cargo.toml (in ffi/) must include:

[lib]
crate-type = ["cdylib"]

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Currently it only builds static libs (staticlib, rlib), which are incompatible with Ruby FFI.

I’m happy to prepare a PR for this change in the Rust repo if the maintainers agree.