pkg/macos: fix zig C ABI issue

pkg/macos/build.zig

@@ -18,7 +18,11 @@ pub fn link(
     opt: Options,
 ) !*std.build.LibExeObjStep {
     _ = opt;
+    var flags = std.ArrayList([]const u8).init(b.allocator);
+    defer flags.deinit();
+
     const lib = b.addStaticLibrary("macos", null);
+    step.addCSourceFile(thisDir() ++ "/text/ext.c", flags.items);
     step.linkFramework("CoreFoundation");
     step.linkFramework("CoreText");
     return lib;

pkg/macos/text/ext.c

@@ -0,0 +1,10 @@
+#include <CoreText/CoreText.h>
+
+// A wrapper to fix a Zig C ABI issue.
+void zig_cabi_CTLineGetBoundsWithOptions(
+    CTLineRef line,
+    CTLineBoundsOptions options,
+    CGRect *result
+) {
+    *result = CTLineGetBoundsWithOptions(line, options);
+}

pkg/macos/text/line.zig

@@ -30,12 +30,30 @@ pub const Line = opaque {
         self: *Line,
         opts: LineBoundsOptions,
     ) graphics.Rect {
-        return @bitCast(c.CGRect, c.CTLineGetBoundsWithOptions(
+        // return @bitCast(c.CGRect, c.CTLineGetBoundsWithOptions(
+        //     @ptrCast(c.CTLineRef, self),
+        //     opts.cval(),
+        // ));
+
+        // We have to use a custom C wrapper here because there is some
+        // C ABI issue happening.
+        var result: graphics.Rect = undefined;
+        zig_cabi_CTLineGetBoundsWithOptions(
             @ptrCast(c.CTLineRef, self),
             opts.cval(),
-        ));
+            @ptrCast(*c.CGRect, &result),
+        );
+
+        return result;
     }
 
+    // See getBoundsWithOptions
+    extern "c" fn zig_cabi_CTLineGetBoundsWithOptions(
+        c.CTLineRef,
+        c.CTLineBoundsOptions,
+        *c.CGRect,
+    ) void;
+
     pub fn getTypographicBounds(
         self: *Line,
         ascent: ?*f64,