build: add -Dxcframework-target to specify the target for builds

Author: mitchellh

build.zig

@@ -98,7 +98,7 @@ pub fn build(b: *std.Build) !void {
         const xcframework = try buildpkg.GhosttyXCFramework.init(
             b,
             &deps,
-            .universal,
+            config.xcframework_target,
         );
         xcframework.install();
 

src/build/Config.zig

@@ -9,6 +9,7 @@ const apprt = @import("../apprt.zig");
 const font = @import("../font/main.zig");
 const rendererpkg = @import("../renderer.zig");
 const Command = @import("../Command.zig");
+const XCFramework = @import("GhosttyXCFramework.zig");
 const WasmTarget = @import("../os/wasm/target.zig").Target;
 
 const gtk = @import("gtk.zig");
@@ -24,6 +25,7 @@ const app_version: std.SemanticVersion = .{ .major = 1, .minor = 1, .patch = 4 }
 /// Standard build configuration options.
 optimize: std.builtin.OptimizeMode,
 target: std.Build.ResolvedTarget,
+xcframework_target: XCFramework.Target = .universal,
 wasm_target: WasmTarget,
 
 /// Comptime interfaces
@@ -109,6 +111,14 @@ pub fn init(b: *std.Build) !Config {
         .env = env,
     };
 
+    //---------------------------------------------------------------
+    // Target-specific properties
+    config.xcframework_target = b.option(
+        XCFramework.Target,
+        "xcframework-target",
+        "The target for the xcframework.",
+    ) orelse .universal;
+
     //---------------------------------------------------------------
     // Comptime Interfaces
     config.font_backend = b.option(