Add support to build the MCP SDK using Linux

[tib]

This PR aims to solve build issues under Linux regarding import Darwin & fcntl.

Motivation and Context

Users should be able to build the SDK using Linux.

How Has This Been Tested?

Added a simple Dockerfile to run the tests.

Breaking Changes

Hopefully none.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation update

Checklist

• I have read the MCP Documentation
• My code follows the repository's style guidelines
• New and existing tests pass locally
• I have added appropriate error handling
• I have added or updated documentation as needed

Additional context

[stallent]

Thank you for doing this. I have been using a fork with the transports removed completely since they were unneeded with a Hummingbird Docker instance.

[tib]

Oh that's nice, do you have a public example of a HB transport using SSE? 🤔

[stallent]

Its not in a public repo at the moment but pretty easy to move to one. I'll try to get that whipped up today.

[mattt]

Oh, hey @tib! Thanks for opening this PR. It'd be great to expand support for Linux as well.

It's too bad that Swift System doesn't yet support fcntl.

I was curious whether we could conditionally compile our way around the problem, so I opened up #61 as a potential alternative. Still have to update CI to test on Linux to know for sure, but can you think of any deal-breakers to that approach?

[tib]

Your PR looks good, the only thing that comes to my mind, is the static Linux SDK support. See this guide, but I don't think my PR supports it, so either solution could work.

Anyway let's get the SDK working on Linux first and then add Musl support afterwards. 😉

[mattt]

Thanks again for opening this PR, @tib. I just merged #61 and opened #63 to add support for Alpine Linux.