Release 2.2.1: universal macOS DMG and arch install fix.

Co-authored-by: Cursor <cursoragent@cursor.com>

tools/mklipo/main.go

@@ -0,0 +1,105 @@
+// mklipo merges two Mach-O binaries into one macOS universal (fat) binary.
+package main
+
+import (
+	"encoding/binary"
+	"fmt"
+	"os"
+)
+
+const (
+	fatMagic      = 0xCAFEBABE
+	cpuTypeX86_64 = 0x01000007
+	cpuTypeARM64  = 0x0100000c
+	fatArchSize   = 20
+)
+
+type slice struct {
+	cpu, sub uint32
+	data     []byte
+}
+
+func main() {
+	if len(os.Args) != 4 {
+		fmt.Fprintln(os.Stderr, "usage: mklipo <amd64-bin> <arm64-bin> <out>")
+		os.Exit(2)
+	}
+	amd, err := os.ReadFile(os.Args[1])
+	if err != nil {
+		fatal(err)
+	}
+	arm, err := os.ReadFile(os.Args[2])
+	if err != nil {
+		fatal(err)
+	}
+	if err := writeFat(os.Args[3], []slice{
+		{cpuTypeX86_64, 3, amd},
+		{cpuTypeARM64, 0, arm},
+	}); err != nil {
+		fatal(err)
+	}
+}
+
+func writeFat(path string, parts []slice) error {
+	const align uint32 = 0x4000
+	hdr := 8 + fatArchSize*len(parts)
+	offsets := make([]uint32, len(parts))
+	cur := uint32(hdr)
+	for i, p := range parts {
+		pad := (align - (cur % align)) % align
+		cur += pad
+		offsets[i] = cur
+		cur += uint32(len(p.data))
+	}
+
+	out, err := os.OpenFile(path, os.O_CREATE|os.O_WRONLY|os.O_TRUNC, 0o755)
+	if err != nil {
+		return err
+	}
+	defer out.Close()
+
+	if err := binary.Write(out, binary.BigEndian, uint32(fatMagic)); err != nil {
+		return err
+	}
+	if err := binary.Write(out, binary.BigEndian, uint32(len(parts))); err != nil {
+		return err
+	}
+	for i, p := range parts {
+		if err := binary.Write(out, binary.BigEndian, p.cpu); err != nil {
+			return err
+		}
+		if err := binary.Write(out, binary.BigEndian, p.sub); err != nil {
+			return err
+		}
+		if err := binary.Write(out, binary.BigEndian, offsets[i]); err != nil {
+			return err
+		}
+		if err := binary.Write(out, binary.BigEndian, uint32(len(p.data))); err != nil {
+			return err
+		}
+		if err := binary.Write(out, binary.BigEndian, align); err != nil {
+			return err
+		}
+	}
+
+	cur = uint32(hdr)
+	for _, p := range parts {
+		pad := (align - (cur % align)) % align
+		if pad > 0 {
+			if _, err := out.Write(make([]byte, pad)); err != nil {
+				return err
+			}
+			cur += pad
+		}
+		if _, err := out.Write(p.data); err != nil {
+			return err
+		}
+		cur += uint32(len(p.data))
+	}
+	return nil
+}
+
+func fatal(err error) {
+	fmt.Fprintln(os.Stderr, "mklipo:", err)
+	os.Exit(1)
+}