build: use apple sdk from xcode

.github/workflows/test.yml

@@ -2,10 +2,7 @@ on: [push, pull_request]
 name: Test
 jobs:
   build:
-    runs-on: macos-12
-    env:
-      # Needed for macos SDK
-      AGREE: "true"
+    runs-on: namespace-profile-ghostty-macos
     steps:
       - name: Checkout code
         uses: actions/checkout@v4

README.md

@@ -73,23 +73,22 @@ const NSOperatingSystemVersion = extern struct {
 
 ## Usage
 
-**Warning:** This project follows the nightly releases of Zig and may
-not work with released versions of Zig until Zig stabilizes. I also
-am **not promising API stability** right now.
-
-Use your favorite Zig package manager or vendor this repository, then add the package.
-For example in your build.zig:
+Add this repository to your `build.zig.zon` file. Then:
 
 ```zig
-const objc = @import("vendor/zig-objc/build.zig");
-
 pub fn build(b: *std.build.Builder) !void {
   // ... other stuff
 
-  exe.addPackage(objc.pkg);
+  exe.root_module.addImport("obcj", b.dependency("zig_objc", .{
+    .target = target,
+    .optimize = optimize,
+  }).module("objc"));
 }
 ```
 
+**`zig-objc` only works with released versions of Zig.** We don't support
+nightly versions because the Zig compiler is still changing too much.
+
 ## Documentation
 
 Read the source code, it is well commented. If something isn't clear, please

build.zig

@@ -1,16 +1,20 @@
 const std = @import("std");
 
-pub fn build(b: *std.Build) void {
+pub fn build(b: *std.Build) !void {
     const optimize = b.standardOptimizeOption(.{});
     const target = b.standardTargetOptions(.{});
-    const add_paths = b.option(bool, "add-paths", "add macos SDK paths from dependency") orelse false;
+    const add_paths = b.option(
+        bool,
+        "add-paths",
+        "add apple SDK paths from Xcode installation",
+    ) orelse true;
 
     const objc = b.addModule("objc", .{
         .root_source_file = b.path("src/main.zig"),
         .target = target,
         .optimize = optimize,
     });
-    if (add_paths) @import("macos_sdk").addPathsModule(objc);
+    if (add_paths) try addAppleSDK(b, objc);
     objc.linkSystemLibrary("objc", .{});
     objc.linkFramework("Foundation", .{});
 
@@ -22,10 +26,61 @@ pub fn build(b: *std.Build) void {
     });
     tests.linkSystemLibrary("objc");
     tests.linkFramework("Foundation");
-    @import("macos_sdk").addPaths(tests);
+    try addAppleSDK(b, &tests.root_module);
     b.installArtifact(tests);
 
     const test_step = b.step("test", "Run tests");
     const tests_run = b.addRunArtifact(tests);
     test_step.dependOn(&tests_run.step);
 }
+
+/// Add the SDK framework, include, and library paths to the given module.
+/// The module target is used to determine the SDK to use so it must have
+/// a resolved target.
+///
+/// The Apple SDK is determined based on the build target and found using
+/// xcrun, so it requires a valid Xcode installation.
+pub fn addAppleSDK(b: *std.Build, m: *std.Build.Module) !void {
+    // The cache. This always uses b.allocator and never frees memory
+    // (which is idiomatic for a Zig build exe).
+    const Cache = struct {
+        const Key = struct {
+            arch: std.Target.Cpu.Arch,
+            os: std.Target.Os.Tag,
+            abi: std.Target.Abi,
+        };
+
+        var map: std.AutoHashMapUnmanaged(Key, ?[]const u8) = .{};
+    };
+
+    const target = m.resolved_target.?.result;
+    const gop = try Cache.map.getOrPut(b.allocator, .{
+        .arch = target.cpu.arch,
+        .os = target.os.tag,
+        .abi = target.abi,
+    });
+
+    // This executes `xcrun` to get the SDK path. We don't want to execute
+    // this multiple times so we cache the value.
+    if (!gop.found_existing) {
+        gop.value_ptr.* = std.zig.system.darwin.getSdk(
+            b.allocator,
+            m.resolved_target.?.result,
+        );
+    }
+
+    // The active SDK we want to use
+    const path = gop.value_ptr.* orelse return switch (target.os.tag) {
+        // Return a more descriptive error. Before we just returned the
+        // generic error but this was confusing a lot of community members.
+        // It costs us nothing in the build script to return something better.
+        .macos => error.XcodeMacOSSDKNotFound,
+        .ios => error.XcodeiOSSDKNotFound,
+        .tvos => error.XcodeTVOSSDKNotFound,
+        .watchos => error.XcodeWatchOSSDKNotFound,
+        else => error.XcodeAppleSDKNotFound,
+    };
+    m.addSystemFrameworkPath(.{ .cwd_relative = b.pathJoin(&.{ path, "/System/Library/Frameworks" }) });
+    m.addSystemIncludePath(.{ .cwd_relative = b.pathJoin(&.{ path, "/usr/include" }) });
+    m.addLibraryPath(.{ .cwd_relative = b.pathJoin(&.{ path, "/usr/lib" }) });
+}

build.zig.zon

@@ -8,10 +8,5 @@
         "README.md",
         "LICENSE",
     },
-    .dependencies = .{
-        .macos_sdk = .{
-            .url = "https://github.com/mitchellh/zig-build-macos-sdk/archive/a4ea24f105902111633c6ae9f888b676ac5e36df.tar.gz",
-            .hash = "12209cc9ee372456eda52b71cf9ae77dcc707fa42c9f9d68996b5bf7495b53229c2e",
-        },
-    },
+    .dependencies = .{},
 }