build: gate lib-vt xcframework on emit-xcframework with xcodebuild detection

build.zig

@@ -154,14 +154,8 @@ pub fn build(b: *std.Build) !void {
 
     // libghostty-vt xcframework (Apple only, universal binary).
     // Only when building on macOS (not cross-compiling) since
-    // optional: requires full xcodebuild. keep lib-vt usable on command-line tools
-    const emit_lib_vt_xcframework = b.option(
-        bool,
-        "emit-lib-vt-xcframework",
-        "Emit libghostty-vt XCFramework (requires xcodebuild/full Xcode).",
-    ) orelse false;
-
-    if (config.emit_lib_vt and emit_lib_vt_xcframework and builtin.os.tag.isDarwin() and config.target.result.os.tag.isDarwin()) {
+    // xcodebuild is required.
+    if (config.emit_lib_vt and config.emit_xcframework and builtin.os.tag.isDarwin() and config.target.result.os.tag.isDarwin()) {
         const apple_libs = try buildpkg.GhosttyLibVt.initStaticAppleUniversal(
             b,
             &config,
@@ -206,8 +200,9 @@ pub fn build(b: *std.Build) !void {
     }
 
     // macOS only artifacts. These will error if they're initialized for
-    // other targets.
-    if (config.target.result.os.tag.isDarwin() and
+    // other targets. In lib-vt mode emit_xcframework controls the lib-vt
+    // xcframework above, not this one.
+    if (!config.emit_lib_vt and config.target.result.os.tag.isDarwin() and
         (config.emit_xcframework or config.emit_macos_app))
     {
         // Ghostty xcframework

example/swift-vt-xcframework/Package.swift

@@ -1,35 +1,6 @@
 // swift-tools-version: 5.9
-import Foundation
 import PackageDescription
 
-func existingXCFrameworkPath() -> String {
-    let fm = FileManager.default
-    let candidates = [
-        "../../zig-out/lib/ghostty-vt.xcframework",
-        "../../zig-out/xcframeworks/ghostty-vt.xcframework",
-        "../../zig-out/ghostty-vt.xcframework",
-    ]
-
-    for rel in candidates {
-        let plist = "\(rel)/Info.plist"
-        var isDir: ObjCBool = false
-        if fm.fileExists(atPath: rel, isDirectory: &isDir),
-            isDir.boolValue,
-            fm.fileExists(atPath: plist)
-        {
-            return rel  // important to return relative path
-        }
-    }
-
-    fatalError(
-        """
-        GhosttyVt XCFramework not found.
-        Build it first (must produce a valid *.xcframework with Info.plist).
-        Tried:
-        \(candidates.joined(separator: "\n"))
-        """)
-}
-
 let package = Package(
     name: "swift-vt-xcframework",
     platforms: [.macOS(.v13)],
@@ -38,11 +9,13 @@ let package = Package(
             name: "swift-vt-xcframework",
             dependencies: ["GhosttyVt"],
             path: "Sources",
-            linkerSettings: [.linkedLibrary("c++")]
+            linkerSettings: [
+                .linkedLibrary("c++"),
+            ]
         ),
         .binaryTarget(
             name: "GhosttyVt",
-            path: existingXCFrameworkPath()
+            path: "../../zig-out/lib/ghostty-vt.xcframework"
         ),
     ]
 )

src/build/Config.zig

@@ -444,13 +444,22 @@ pub fn init(b: *std.Build, appVersion: []const u8, libVersion: []const u8) !Conf
         bool,
         "emit-xcframework",
         "Build and install the xcframework for the macOS library.",
-    ) orelse !config.emit_lib_vt and
-        builtin.target.os.tag.isDarwin() and
-        target.result.os.tag == .macos and
-        config.app_runtime == .none and
-        (!config.emit_bench and
-            !config.emit_test_exe and
-            !config.emit_helpgen);
+    ) orelse emit_xcfw: {
+        if (!builtin.target.os.tag.isDarwin() or target.result.os.tag != .macos)
+            break :emit_xcfw false;
+        if (config.emit_lib_vt) {
+            // In lib-vt mode default to whether xcodebuild is available,
+            // since xcodebuild is required to produce the XCFramework.
+            const path = expandPath(b.allocator, "xcodebuild") catch
+                break :emit_xcfw false;
+            defer if (path) |p| b.allocator.free(p);
+            break :emit_xcfw path != null;
+        }
+        break :emit_xcfw config.app_runtime == .none and
+            (!config.emit_bench and
+                !config.emit_test_exe and
+                !config.emit_helpgen);
+    };
 
     config.emit_macos_app = b.option(
         bool,