Support AArch64 ILP32 in libunwind bindings

Author: Amanieu d'Antras

library/unwind/src/libunwind.rs

@@ -36,9 +36,12 @@ pub const unwinder_private_data_size: usize = 20;
 #[cfg(all(target_arch = "arm", target_os = "ios"))]
 pub const unwinder_private_data_size: usize = 5;
 
-#[cfg(target_arch = "aarch64")]
+#[cfg(all(target_arch = "aarch64", target_pointer_width = "64"))]
 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 = "mips")]
 pub const unwinder_private_data_size: usize = 2;