diff --git a/src/elf.rs b/src/elf.rs
index da68ec2d..f202c598 100644
--- a/src/elf.rs
+++ b/src/elf.rs
@@ -1921,6 +1921,7 @@ pub const GNU_PROPERTY_HIUSER: u32 = 0xffffffff;
 
 /// AArch64 specific GNU properties.
 pub const GNU_PROPERTY_AARCH64_FEATURE_1_AND: u32 = 0xc0000000;
+pub const GNU_PROPERTY_AARCH64_FEATURE_PAUTH: u32 = 0xc0000001;
 
 pub const GNU_PROPERTY_AARCH64_FEATURE_1_BTI: u32 = 1 << 0;
 pub const GNU_PROPERTY_AARCH64_FEATURE_1_PAC: u32 = 1 << 1;
diff --git a/src/write/coff.rs b/src/write/coff.rs
index d2f7ccc6..2277a08e 100644
--- a/src/write/coff.rs
+++ b/src/write/coff.rs
@@ -83,7 +83,7 @@ impl<'a> Object<'a> {
         name
     }
 
-    pub(crate) fn coff_fixup_relocation(&mut self, mut relocation: &mut Relocation) -> i64 {
+    pub(crate) fn coff_fixup_relocation(&mut self, relocation: &mut Relocation) -> i64 {
         if relocation.kind == RelocationKind::GotRelative {
             // Use a stub symbol for the relocation instead.
             // This isn't really a GOT, but it's a similar purpose.
diff --git a/src/write/elf/object.rs b/src/write/elf/object.rs
index acc820c9..421d23a8 100644
--- a/src/write/elf/object.rs
+++ b/src/write/elf/object.rs
@@ -152,7 +152,7 @@ impl<'a> Object<'a> {
         })
     }
 
-    pub(crate) fn elf_fixup_relocation(&mut self, mut relocation: &mut Relocation) -> Result<i64> {
+    pub(crate) fn elf_fixup_relocation(&mut self, relocation: &mut Relocation) -> Result<i64> {
         // Return true if we should use a section symbol to avoid preemption.
         fn want_section_symbol(relocation: &Relocation, symbol: &Symbol) -> bool {
             if symbol.scope != SymbolScope::Dynamic {
diff --git a/src/write/macho.rs b/src/write/macho.rs
index e3ce55bb..05c376cf 100644
--- a/src/write/macho.rs
+++ b/src/write/macho.rs
@@ -48,6 +48,14 @@ impl MachOBuildVersion {
 
 // Public methods.
 impl<'a> Object<'a> {
+    /// Specify the Mach-O CPU subtype.
+    ///
+    /// Requires `feature = "macho"`.
+    #[inline]
+    pub fn set_macho_cpu_subtype(&mut self, cpu_subtype: u32) {
+        self.macho_cpu_subtype = Some(cpu_subtype);
+    }
+
     /// Specify information for a Mach-O `LC_BUILD_VERSION` command.
     ///
     /// Requires `feature = "macho"`.
@@ -243,7 +251,7 @@ impl<'a> Object<'a> {
         init_symbol_id
     }
 
-    pub(crate) fn macho_fixup_relocation(&mut self, mut relocation: &mut Relocation) -> i64 {
+    pub(crate) fn macho_fixup_relocation(&mut self, relocation: &mut Relocation) -> i64 {
         let constant = match relocation.kind {
             // AArch64Call relocations have special handling for the addend, so don't adjust it
             RelocationKind::Relative if relocation.encoding == RelocationEncoding::AArch64Call => 0,
@@ -385,7 +393,7 @@ impl<'a> Object<'a> {
             .map_err(|_| Error(String::from("Cannot allocate buffer")))?;
 
         // Write file header.
-        let (cputype, cpusubtype) = match self.architecture {
+        let (cputype, mut 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 => {
@@ -403,6 +411,10 @@ impl<'a> Object<'a> {
             }
         };
 
+        if let Some(cpu_subtype) = self.macho_cpu_subtype {
+            cpusubtype = cpu_subtype;
+        }
+
         let flags = match self.flags {
             FileFlags::MachO { flags } => flags,
             _ => 0,
diff --git a/src/write/mod.rs b/src/write/mod.rs
index 711ff16d..15ca29d7 100644
--- a/src/write/mod.rs
+++ b/src/write/mod.rs
@@ -75,6 +75,9 @@ pub struct Object<'a> {
     pub mangling: Mangling,
     /// Mach-O "_tlv_bootstrap" symbol.
     tlv_bootstrap: Option<SymbolId>,
+    /// Mach-O CPU subtype.
+    #[cfg(feature = "macho")]
+    macho_cpu_subtype: Option<u32>,
     #[cfg(feature = "macho")]
     macho_build_version: Option<MachOBuildVersion>,
 }
@@ -96,6 +99,8 @@ impl<'a> Object<'a> {
             mangling: Mangling::default(format, architecture),
             tlv_bootstrap: None,
             #[cfg(feature = "macho")]
+            macho_cpu_subtype: None,
+            #[cfg(feature = "macho")]
             macho_build_version: None,
         }
     }
diff --git a/src/write/xcoff.rs b/src/write/xcoff.rs
index 6c9a8038..fc58886e 100644
--- a/src/write/xcoff.rs
+++ b/src/write/xcoff.rs
@@ -66,7 +66,7 @@ impl<'a> Object<'a> {
         }
     }
 
-    pub(crate) fn xcoff_fixup_relocation(&mut self, mut relocation: &mut Relocation) -> i64 {
+    pub(crate) fn xcoff_fixup_relocation(&mut self, relocation: &mut Relocation) -> i64 {
         let constant = match relocation.kind {
             RelocationKind::Relative => relocation.addend + 4,
             _ => relocation.addend,