restructure cap-std impls into their own crate

crates/wasi-c2/cap-std-sync/src/stdio.rs

@@ -0,0 +1,63 @@
+use wasi_c2::pipe::{ReadPipe, WritePipe};
+
+pub type Stdin = ReadPipe<std::io::Stdin>;
+
+pub fn stdin() -> Stdin {
+    ReadPipe::new(std::io::stdin())
+}
+
+pub type Stdout = WritePipe<std::io::Stdout>;
+
+pub fn stdout() -> Stdout {
+    WritePipe::new(std::io::stdout())
+}
+
+pub type Stderr = WritePipe<std::io::Stderr>;
+
+pub fn stderr() -> Stderr {
+    WritePipe::new(std::io::stderr())
+}
+
+/*
+#[cfg(windows)]
+mod windows {
+    use super::*;
+    use std::os::windows::io::{AsRawHandle, RawHandle};
+    impl AsRawHandle for Stdin {
+        fn as_raw_handle(&self) -> RawHandle {
+            self.borrow().as_raw_handle()
+        }
+    }
+    impl AsRawHandle for Stdout {
+        fn as_raw_handle(&self) -> RawHandle {
+            self.borrow().as_raw_handle()
+        }
+    }
+    impl AsRawHandle for Stderr {
+        fn as_raw_handle(&self) -> RawHandle {
+            self.borrow().as_raw_handle()
+        }
+    }
+}
+
+#[cfg(unix)]
+mod unix {
+    use super::*;
+    use std::os::unix::io::{AsRawFd, RawFd};
+    impl AsRawFd for Stdin {
+        fn as_raw_fd(&self) -> RawFd {
+            self.borrow().as_raw_fd()
+        }
+    }
+    impl AsRawFd for Stdout {
+        fn as_raw_fd(&self) -> RawFd {
+            self.borrow().as_raw_fd()
+        }
+    }
+    impl AsRawFd for Stderr {
+        fn as_raw_fd(&self) -> RawFd {
+            self.borrow().as_raw_fd()
+        }
+    }
+}
+*/