library/unwind: Define unwinder_private_data_size for m68k

Author: glaubitz

library/unwind/src/libunwind.rs

@@ -42,6 +42,9 @@ pub const unwinder_private_data_size: usize = 2;
 #[cfg(all(target_arch = "aarch64", target_pointer_width = "32"))]
 pub const unwinder_private_data_size: usize = 5;
 
+#[cfg(target_arch = "m68k")]
+pub const unwinder_private_data_size: usize = 2;
+
 #[cfg(target_arch = "mips")]
 pub const unwinder_private_data_size: usize = 2;