mach/system-sdk, more libraries for cross-compilation with Zig

Updated DirectX 12 headers for use with MinGW/Zig
Cross-compile DirectX apps targetting Windows
Cross compile Metal apps targetting macOS/iOS Intel or Apple Silicon.
Cross compile OpenGL/Vulkan apps targetting Linux (not other OSs, sorry)

What is this?

One thing I care about extremely with Mach engine is that you're able to cross compile for any OS with nothing more than zig and git. And while we can build most things from source (GLFW, and even the DirectX Shader Compiler!) there are a few system headers / libraries where, really, we just need a copy of them.

mach/system-sdk is how Mach engine gets a copy of them via the Zig build system.

Although it was intended for Mach specifically, and I wouldn't be surprised if one day Zig provides better options out of the box, I realize others might benefit from this and so I've made it easy for anyone to use!

What does it provide?

Depending on the target OS, system_sdk.zig will automatically git clone the relevant system SDK for you and include it:

sdk-windows-x86_64 (~7MB):
- Updated DirectX 12 headers (and prior versions) for use with Zig/MinGW when specifying a -Dtarget=x86_64-windows-gnu target.
- DirectX libraries such as dxgi.lib and dxguid.lib
sdk-linux-x86_64 (~40MB):
- X11/xcb/Wayland libraries/headers (as static as possible)
- OpenGL and Vulkan headers
- Generated Wayland protocol sources
sdk-macos-11.3 (~198MB) and sdk-macos-12.0 (~149MB)
- A nearly full copy of the macOS 11.3 and 12.0 XCode SDKs, with just a few particularly large frameworks excluded.
- Pretty much every framework, header, etc. that you need to develop macOS and iOS applications for Intel and Apple Silicon.
- Symlinks mostly eliminated for ease of use on Windows

The build script will git clone these SDKs for you, pin them to a specific Git revision denoted in the system_sdk.zig file so they are versioned, and even prompt for XCode license agreement in the case of macOS SDKs.

into the appdata directory

/Users/slimsag/Library/Application Support/hexops

Single file & one-liner to use

Get system_sdk.zig into your codebase however you prefer. I suggest just copying it for now, it's a single file.

In your build.zig:

const system_sdk = @import("system_sdk.zig");
...
system_sdk.include(b, step, .{});

Where step is the exe / lib you're building.

Shared between Zig projects

The SDKs are cloned into your <appdata>/hexops directory to ensure they are shared across projects and you don't end up with multiple copies. Prior to use the build script will git reset to the target revision.

Customization

If you don't like what is provided in the SDK repositories, I've tried to make it as easy as possible to switch to your own SDK repos. Just pass Options:

system_sdk.include(b, step, .{
    .github_org = "myorg",
    .linux_x86_64_revision = "ab7fa8f3a05b06e0b06f4277b484e27004bfb20f",
    .windows_x86_64_revision = "5acba990efd112ea0ced364f0428e6ef6e7a5541",
});

And set the revisions to the Git revisions of your forks of the SDK repositories.

Is this the right way to do this? Should I be using this?

To be clear, I don't think this is the perfect way or 100% ideal way to handle this. I am positive that the Zig community will eventually land on better solutions here.

For example, generating updated DirectX 12 headers for MinGW/Zig requires patching Microsoft's IDL files, running them through the Wine WIDL compiler, and then some. Storing even a few binaries in Git is not ideal, even if we do clone with --depth 1.

But, if you care about that developer experience as immensely as I do I hope you'll see a bit of reason behind the madness.

Use at your own peril!

Issues

Please file issues/complaints in the main Mach repository.

hexops / mach-system-sdk