Provide NonZero_c_* integers

I'm pretty sure I am going want this for rust-lang#73125 and it seems like an
omission that would be in any case good to remedy.

It's a shame we don't have competent token pasting and case mangling
for use in macro_rules!.

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

library/std/src/lib.rs

@@ -263,6 +263,7 @@
 #![feature(exact_size_is_empty)]
 #![feature(exhaustive_patterns)]
 #![feature(extend_one)]
+#![feature(extended_key_value_attributes)]
 #![feature(external_doc)]
 #![feature(fn_traits)]
 #![feature(format_args_nl)]

library/std/src/os/raw/mod.rs

@@ -11,16 +11,41 @@
 #[cfg(test)]
 mod tests;
 
-macro_rules! type_alias {
-    { $Docfile:tt, $Alias:ident = $Real:ty; $( $Cfg:tt )* } => {
+use core::num::*;
+
+macro_rules! type_alias_no_nz {
+    {
+      $Docfile:tt, $Alias:ident = $Real:ty;
+      $( $Cfg:tt )*
+    } => {
         #[doc(include = $Docfile)]
         $( $Cfg )*
         #[stable(feature = "raw_os", since = "1.1.0")]
         pub type $Alias = $Real;
     }
 }
 
-type_alias! { "char.md", c_char = u8;
+// To verify that the NonZero types in this file's macro invocations correspond
+//
+//  perl -n < library/std/src/os/raw/mod.rs -e 'next unless m/type_alias\!/; die "$_ ?" unless m/, (c_\w+) = (\w+), NonZero_(\w+) = NonZero(\w+)/; die "$_ ?" unless $3 eq $1 and $4 eq ucfirst $2'
+//
+// NB this does not check that the main c_* types are right.
+
+macro_rules! type_alias {
+    {
+      $Docfile:tt, $Alias:ident = $Real:ty, $NZAlias:ident = $NZReal:ty;
+      $( $Cfg:tt )*
+    } => {
+        type_alias_no_nz! { $Docfile, $Alias = $Real; $( $Cfg )* }
+
+        #[doc = concat!("Type alias for `NonZero` version of [`", stringify!($Alias), "`]")]
+        #[unstable(feature = "raw_os_nonzero", issue = "none")]
+        $( $Cfg )*
+        pub type $NZAlias = $NZReal;
+    }
+}
+
+type_alias! { "char.md", c_char = u8, NonZero_c_char = NonZeroU8;
 #[cfg(any(
     all(
         target_os = "linux",
@@ -62,7 +87,7 @@ type_alias! { "char.md", c_char = u8;
     ),
     all(target_os = "fuchsia", target_arch = "aarch64")
 ))]}
-type_alias! { "char.md", c_char = i8;
+type_alias! { "char.md", c_char = i8, NonZero_c_char = NonZeroI8;
 #[cfg(not(any(
     all(
         target_os = "linux",
@@ -104,20 +129,24 @@ type_alias! { "char.md", c_char = i8;
     ),
     all(target_os = "fuchsia", target_arch = "aarch64")
 )))]}
-type_alias! { "schar.md", c_schar = i8; }
-type_alias! { "uchar.md", c_uchar = u8; }
-type_alias! { "short.md", c_short = i16; }
-type_alias! { "ushort.md", c_ushort = u16; }
-type_alias! { "int.md", c_int = i32; }
-type_alias! { "uint.md", c_uint = u32; }
-type_alias! { "long.md", c_long = i32; #[cfg(any(target_pointer_width = "32", windows))] }
-type_alias! { "ulong.md", c_ulong = u32; #[cfg(any(target_pointer_width = "32", windows))] }
-type_alias! { "long.md", c_long = i64; #[cfg(all(target_pointer_width = "64", not(windows)))] }
-type_alias! { "ulong.md", c_ulong = u64; #[cfg(all(target_pointer_width = "64", not(windows)))] }
-type_alias! { "longlong.md", c_longlong = i64; }
-type_alias! { "ulonglong.md", c_ulonglong = u64; }
-type_alias! { "float.md", c_float = f32; }
-type_alias! { "double.md", c_double = f64; }
+type_alias! { "schar.md", c_schar = i8, NonZero_c_schar = NonZeroI8; }
+type_alias! { "uchar.md", c_uchar = u8, NonZero_c_uchar = NonZeroU8; }
+type_alias! { "short.md", c_short = i16, NonZero_c_short = NonZeroI16; }
+type_alias! { "ushort.md", c_ushort = u16, NonZero_c_ushort = NonZeroU16; }
+type_alias! { "int.md", c_int = i32, NonZero_c_int = NonZeroI32; }
+type_alias! { "uint.md", c_uint = u32, NonZero_c_uint = NonZeroU32; }
+type_alias! { "long.md", c_long = i32, NonZero_c_long = NonZeroI32;
+#[cfg(any(target_pointer_width = "32", windows))] }
+type_alias! { "ulong.md", c_ulong = u32, NonZero_c_ulong = NonZeroU32;
+#[cfg(any(target_pointer_width = "32", windows))] }
+type_alias! { "long.md", c_long = i64, NonZero_c_long = NonZeroI64;
+#[cfg(all(target_pointer_width = "64", not(windows)))] }
+type_alias! { "ulong.md", c_ulong = u64, NonZero_c_ulong = NonZeroU64;
+#[cfg(all(target_pointer_width = "64", not(windows)))] }
+type_alias! { "longlong.md", c_longlong = i64, NonZero_c_longlong = NonZeroI64; }
+type_alias! { "ulonglong.md", c_ulonglong = u64, NonZero_c_ulonglong = NonZeroU64; }
+type_alias_no_nz! { "float.md", c_float = f32; }
+type_alias_no_nz! { "double.md", c_double = f64; }
 
 #[stable(feature = "raw_os", since = "1.1.0")]
 #[doc(no_inline)]