Auto merge of #136780 - joboet:move_pal_stdio, r=Amanieu

std: move stdio to `sys`

As per #117276, this moves the platform definitions of `Stdout` and friends into `sys`. This PR also unifies the UNIX and Hermit implementations and moves the `__rust_print_err` function needed by libunwind on SGX into the dedicated module for such helper functions.

1 files changed, 59 insertions, 0 deletions

diff --git a/library/std/src/sys/stdio/unsupported.rs b/library/std/src/sys/stdio/unsupported.rs
new file mode 100644
index 00000000000..b5e3f5be988
--- /dev/null
+++ b/library/std/src/sys/stdio/unsupported.rs
@@ -0,0 +1,59 @@
+use crate::io;
+
+pub struct Stdin;
+pub struct Stdout;
+pub struct Stderr;
+
+impl Stdin {
+    pub const fn new() -> Stdin {
+        Stdin
+    }
+}
+
+impl io::Read for Stdin {
+    fn read(&mut self, _buf: &mut [u8]) -> io::Result<usize> {
+        Ok(0)
+    }
+}
+
+impl Stdout {
+    pub const fn new() -> Stdout {
+        Stdout
+    }
+}
+
+impl io::Write for Stdout {
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        Ok(buf.len())
+    }
+
+    fn flush(&mut self) -> io::Result<()> {
+        Ok(())
+    }
+}
+
+impl Stderr {
+    pub const fn new() -> Stderr {
+        Stderr
+    }
+}
+
+impl io::Write for Stderr {
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        Ok(buf.len())
+    }
+
+    fn flush(&mut self) -> io::Result<()> {
+        Ok(())
+    }
+}
+
+pub const STDIN_BUF_SIZE: usize = 0;
+
+pub fn is_ebadf(_err: &io::Error) -> bool {
+    true
+}
+
+pub fn panic_output() -> Option<Vec<u8>> {
+    None
+}