Add macOS universal cross file

cross/macos-universal.txt

@@ -0,0 +1,20 @@
+[host_machine]
+cpu_family = 'aarch64'
+cpu = 'aarch64'
+system = 'darwin'
+endian = 'little'
+
+[properties]
+needs_exe_wrapper = false
+
+[binaries]
+c = 'cc'
+cpp = 'c++'
+strip = 'strip'
+
+[built-in options]
+c_args = ['-arch', 'arm64', '-arch', 'x86_64']
+cpp_args = ['-arch', 'arm64', '-arch', 'x86_64']
+cpp_link_args = ['-arch', 'arm64', '-arch', 'x86_64']
+
+