Update libc crate to 0.2.55

This change updates the libc crate to version 0.2.55.

Import subrepo libc/:libc at caf17a0641d29dc624621177f5756804dd180c13

1 files changed, 93 insertions, 27 deletions

diff --git a/libc/src/macros.rs b/libc/src/macros.rs
index 7720578..c48ae8b 100644
--- a/libc/src/macros.rs
+++ b/libc/src/macros.rs
@@ -6,46 +6,116 @@
 ///
 /// This allows you to conveniently provide a long list #[cfg]'d blocks of code
 /// without having to rewrite each clause multiple times.
+#[allow(unused_macros)]
 macro_rules! cfg_if {
+    // match if/else chains with a final `else`
     ($(
         if #[cfg($($meta:meta),*)] { $($it:item)* }
     ) else * else {
         $($it2:item)*
     }) => {
-        __cfg_if_items! {
+        cfg_if! {
+            @__items
             () ;
             $( ( ($($meta),*) ($($it)*) ), )*
             ( () ($($it2)*) ),
         }
-    }
-}
+    };
 
-macro_rules! __cfg_if_items {
-    (($($not:meta,)*) ; ) => {};
-    (($($not:meta,)*) ; ( ($($m:meta),*) ($($it:item)*) ), $($rest:tt)*) => {
-        __cfg_if_apply! { cfg(all(not(any($($not),*)), $($m,)*)), $($it)* }
-        __cfg_if_items! { ($($not,)* $($m,)*) ; $($rest)* }
-    }
-}
+    // match if/else chains lacking a final `else`
+    (
+        if #[cfg($($i_met:meta),*)] { $($i_it:item)* }
+        $(
+            else if #[cfg($($e_met:meta),*)] { $($e_it:item)* }
+        )*
+    ) => {
+        cfg_if! {
+            @__items
+            () ;
+            ( ($($i_met),*) ($($i_it)*) ),
+            $( ( ($($e_met),*) ($($e_it)*) ), )*
+            ( () () ),
+        }
+    };
+
+    // Internal and recursive macro to emit all the items
+    //
+    // Collects all the negated cfgs in a list at the beginning and after the
+    // semicolon is all the remaining items
+    (@__items ($($not:meta,)*) ; ) => {};
+    (@__items ($($not:meta,)*) ; ( ($($m:meta),*) ($($it:item)*) ),
+     $($rest:tt)*) => {
+        // Emit all items within one block, applying an approprate #[cfg]. The
+        // #[cfg] will require all `$m` matchers specified and must also negate
+        // all previous matchers.
+        cfg_if! { @__apply cfg(all($($m,)* not(any($($not),*)))), $($it)* }
 
-macro_rules! __cfg_if_apply {
-    ($m:meta, $($it:item)*) => {
+        // Recurse to emit all other items in `$rest`, and when we do so add all
+        // our `$m` matchers to the list of `$not` matchers as future emissions
+        // will have to negate everything we just matched as well.
+        cfg_if! { @__items ($($not,)* $($m,)*) ; $($rest)* }
+    };
+
+    // Internal macro to Apply a cfg attribute to a list of items
+    (@__apply $m:meta, $($it:item)*) => {
         $(#[$m] $it)*
-    }
+    };
 }
 
+#[allow(unused_macros)]
 macro_rules! s {
     ($($(#[$attr:meta])* pub $t:ident $i:ident { $($field:tt)* })*) => ($(
+        s!(it: $(#[$attr])* pub $t $i { $($field)* });
+    )*);
+    (it: $(#[$attr:meta])* pub union $i:ident { $($field:tt)* }) => (
+        compile_error!("unions cannot derive extra traits, use s_no_extra_traits instead");
+    );
+    (it: $(#[$attr:meta])* pub struct $i:ident { $($field:tt)* }) => (
         __item! {
             #[repr(C)]
+            #[cfg_attr(feature = "extra_traits", derive(Debug, Eq, Hash, PartialEq))]
             $(#[$attr])*
-            pub $t $i { $($field)* }
+            pub struct $i { $($field)* }
         }
-        impl ::dox::Copy for $i {}
-        impl ::dox::Clone for $i {
+        impl ::Copy for $i {}
+        impl ::Clone for $i {
             fn clone(&self) -> $i { *self }
         }
-    )*)
+    );
+}
+
+#[allow(unused_macros)]
+macro_rules! s_no_extra_traits {
+    ($($(#[$attr:meta])* pub $t:ident $i:ident { $($field:tt)* })*) => ($(
+        s_no_extra_traits!(it: $(#[$attr])* pub $t $i { $($field)* });
+    )*);
+    (it: $(#[$attr:meta])* pub union $i:ident { $($field:tt)* }) => (
+        cfg_if! {
+            if #[cfg(libc_union)] {
+                __item! {
+                    #[repr(C)]
+                    $(#[$attr])*
+                    pub union $i { $($field)* }
+                }
+
+                impl ::Copy for $i {}
+                impl ::Clone for $i {
+                    fn clone(&self) -> $i { *self }
+                }
+            }
+        }
+    );
+    (it: $(#[$attr:meta])* pub struct $i:ident { $($field:tt)* }) => (
+        __item! {
+            #[repr(C)]
+            $(#[$attr])*
+            pub struct $i { $($field)* }
+        }
+        impl ::Copy for $i {}
+        impl ::Clone for $i {
+            fn clone(&self) -> $i { *self }
+        }
+    );
 }
 
 #[allow(unused_macros)]
@@ -54,19 +124,13 @@ macro_rules! f {
         $($body:stmt);*
     })*) => ($(
         #[inline]
-        #[cfg(not(cross_platform_docs))]
         pub unsafe extern fn $i($($arg: $argty),*) -> $ret {
             $($body);*
         }
-
-        #[cfg(cross_platform_docs)]
-        #[allow(dead_code)]
-        pub unsafe extern fn $i($($arg: $argty),*) -> $ret {
-            loop {}
-        }
     )*)
 }
 
+#[allow(unused_macros)]
 macro_rules! __item {
     ($i:item) => {
         $i
@@ -75,13 +139,15 @@ macro_rules! __item {
 
 #[allow(unused_macros)]
 macro_rules! align_const {
-    ($($(#[$attr:meta])* pub const $name:ident : $t1:ty = $t2:ident { $($field:tt)* };)*) => ($(
-        #[cfg(feature = "align")]
+    ($($(#[$attr:meta])*
+       pub const $name:ident : $t1:ty
+       = $t2:ident { $($field:tt)* };)*) => ($(
+        #[cfg(libc_align)]
         $(#[$attr])*
         pub const $name : $t1 = $t2 {
             $($field)*
         };
-        #[cfg(not(feature = "align"))]
+        #[cfg(not(libc_align))]
         $(#[$attr])*
         pub const $name : $t1 = $t2 {
             $($field)*