Move RawOsError defination to sys

Signed-off-by: Ayush Singh <ayushdevel1325@gmail.com>

Author: Ayush1325

library/std/src/io/error.rs

@@ -102,7 +102,7 @@ enum ErrorData<C> {
 ///
 /// [`into`]: Into::into
 #[unstable(feature = "raw_os_error_ty", issue = "107792")]
-pub type RawOsError = i32;
+pub type RawOsError = sys::RawOsError;
 
 // `#[repr(align(4))]` is probably redundant, it should have that value or
 // higher already. We include it just because repr_bitpacked.rs's encoding

library/std/src/io/error/repr_bitpacked.rs

@@ -374,9 +374,6 @@ static_assert!((TAG_MASK + 1).is_power_of_two());
 static_assert!(align_of::<SimpleMessage>() >= TAG_MASK + 1);
 static_assert!(align_of::<Custom>() >= TAG_MASK + 1);
 
-// `RawOsError` must be an alias for `i32`.
-const _: fn(RawOsError) -> i32 = |os| os;
-
 static_assert!(@usize_eq: TAG_MASK & TAG_SIMPLE_MESSAGE, TAG_SIMPLE_MESSAGE);
 static_assert!(@usize_eq: TAG_MASK & TAG_CUSTOM, TAG_CUSTOM);
 static_assert!(@usize_eq: TAG_MASK & TAG_OS, TAG_OS);

library/std/src/sys/mod.rs

@@ -110,3 +110,5 @@ pub fn log_wrapper<F: Fn(f64) -> f64>(n: f64, log_fn: F) -> f64 {
 pub fn log_wrapper<F: Fn(f64) -> f64>(n: f64, log_fn: F) -> f64 {
     log_fn(n)
 }
+
+pub type RawOsError = i32;