Add more from the std

library/std/src/sys/fd/mod.rs

@@ -0,0 +1,23 @@
+//! Platform-dependent file descriptor abstraction.
+
+#![forbid(unsafe_op_in_unsafe_fn)]
+
+cfg_select! {
+    any(target_family = "unix", target_os = "wasi") => {
+        mod unix;
+        pub use unix::*;
+    }
+    target_os = "hermit" => {
+        mod hermit;
+        pub use hermit::*;
+    }
+    target_os = "motor" => {
+        mod motor;
+        pub use motor::*;
+    }
+    all(target_vendor = "fortanix", target_env = "sgx") => {
+        mod sgx;
+        pub use sgx::*;
+    }
+    _ => {}
+}