diff --git a/libc-test/build.rs b/libc-test/build.rs
index 4288084675141..7d4e9c0f469d5 100644
--- a/libc-test/build.rs
+++ b/libc-test/build.rs
@@ -296,6 +296,9 @@ fn test_apple(target: &str) {
     }
 
     cfg.skip_struct(move |ty| {
+        if ty.starts_with("__c_anonymous_") {
+            return true;
+        }
         match ty {
             // FIXME: actually a union
             "sigval" => true,
diff --git a/src/unix/mod.rs b/src/unix/mod.rs
index 826b835182a82..69ecd202c4892 100644
--- a/src/unix/mod.rs
+++ b/src/unix/mod.rs
@@ -25,7 +25,7 @@ pub type ssize_t = isize;
 pub type pid_t = i32;
 pub type in_addr_t = u32;
 pub type in_port_t = u16;
-pub type sighandler_t = ::size_t;
+pub type sighandler_t = __c_anonymous_sigaction_handler;
 pub type cc_t = ::c_uchar;
 
 cfg_if! {
@@ -51,6 +51,18 @@ impl ::Clone for DIR {
 }
 pub type locale_t = *mut ::c_void;
 
+s_no_extra_traits! {
+    pub union __c_anonymous_sigaction_handler {
+        pub sa_handler: Option<extern "C" fn(c_int) -> ()>,
+        pub sa_sigaction: Option<extern "C" fn(
+            c_int,
+            *mut siginfo_t,
+            *mut c_void
+        ) -> ()>,
+        pub default: size_t,
+    }
+}
+
 s! {
     pub struct group {
         pub gr_name: *mut ::c_char,
@@ -206,12 +218,36 @@ s! {
     }
 }
 
+cfg_if! {
+    if #[cfg(feature = "extra_traits")] {
+        impl PartialEq for __c_anonymous_sigaction_handler {
+            fn eq(&self, other: &__c_anonymous_sigaction_handler) -> bool {
+                unsafe { self.default == other.default }
+            }
+        }
+        impl Eq for __c_anonymous_sigaction_handler {}
+        impl ::fmt::Debug for __c_anonymous_sigaction_handler {
+            fn fmt(&self, f: &mut ::fmt::Formatter) -> ::fmt::Result {
+                f.debug_struct("sigaction_t")
+                    .field("value", unsafe { &self.default } )
+                    .finish()
+            }
+        }
+        impl ::hash::Hash for __c_anonymous_sigaction_handler {
+            fn hash<H: ::hash::Hasher>(&self, state: &mut H) {
+                unsafe { self.default.hash(state) };
+            }
+        }
+    }
+}
+
 pub const INT_MIN: c_int = -2147483648;
 pub const INT_MAX: c_int = 2147483647;
 
-pub const SIG_DFL: sighandler_t = 0 as sighandler_t;
-pub const SIG_IGN: sighandler_t = 1 as sighandler_t;
-pub const SIG_ERR: sighandler_t = !0 as sighandler_t;
+pub const SIG_DFL: sighandler_t = sighandler_t { default: 0 };
+pub const SIG_IGN: sighandler_t = sighandler_t { default: 1 };
+pub const SIG_ERR: sighandler_t = sighandler_t { default: !0 };
+
 cfg_if! {
     if #[cfg(not(target_os = "nto"))] {
         pub const DT_UNKNOWN: u8 = 0;
@@ -224,6 +260,7 @@ cfg_if! {
         pub const DT_SOCK: u8 = 12;
     }
 }
+
 cfg_if! {
     if #[cfg(not(target_os = "redox"))] {
         pub const FD_CLOEXEC: ::c_int = 0x1;