Support Aarch64_Ilp32 architectire for mac, as used by arm64_32-apple…

…-watchos compile target.

Rust issue: rust-lang/rust#111217

src/write/macho.rs

@@ -398,6 +398,7 @@ impl<'a> Object<'a> {
         let (cputype, cpusubtype) = match self.architecture {
             Architecture::Arm => (macho::CPU_TYPE_ARM, macho::CPU_SUBTYPE_ARM_ALL),
             Architecture::Aarch64 => (macho::CPU_TYPE_ARM64, macho::CPU_SUBTYPE_ARM64_ALL),
+            Architecture::Aarch64_Ilp32 => (macho::CPU_TYPE_ARM64_32, macho::CPU_SUBTYPE_ARM64_32_V8),
             Architecture::I386 => (macho::CPU_TYPE_X86, macho::CPU_SUBTYPE_I386_ALL),
             Architecture::X86_64 => (macho::CPU_TYPE_X86_64, macho::CPU_SUBTYPE_X86_64_ALL),
             Architecture::PowerPc => (macho::CPU_TYPE_POWERPC, macho::CPU_SUBTYPE_POWERPC_ALL),