Refactor yes to remove libc dependency

Yes, using libc while using nix waas a bit redundant.

src/uu/yes/Cargo.toml

@@ -16,11 +16,10 @@ path = "src/yes.rs"
 
 [dependencies]
 clap = { workspace=true }
-libc = { workspace=true }
 uucore = { workspace=true, features=["pipes"] }
 
-[target.'cfg(any(target_os = "linux", target_os = "android"))'.dependencies]
-nix = { workspace=true }
+[target.'cfg(unix)'.dependencies]
+nix = { workspace=true, features = ["signal"] }
 
 [[bin]]
 name = "yes"

src/uu/yes/src/yes.rs

@@ -8,9 +8,11 @@
 /* last synced with: yes (GNU coreutils) 8.13 */
 
 use std::borrow::Cow;
-use std::io::{self, Result, Write};
+use std::io::{self, Error, ErrorKind, Result, Write};
 
 use clap::{Arg, ArgAction, Command};
+#[cfg(unix)]
+use nix::sys::signal::{signal, SigHandler::SigDfl, Signal::SIGPIPE};
 use uucore::error::{UResult, USimpleError};
 use uucore::{format_usage, help_about, help_usage};
 
@@ -71,11 +73,11 @@ fn prepare_buffer<'a>(input: &'a str, buffer: &'a mut [u8; BUF_SIZE]) -> &'a [u8
 
 #[cfg(unix)]
 fn enable_pipe_errors() -> Result<()> {
-    let ret = unsafe { libc::signal(libc::SIGPIPE, libc::SIG_DFL) };
-    if ret == libc::SIG_ERR {
-        return Err(io::Error::new(io::ErrorKind::Other, ""));
+    // SAFETY: this function is safe as long as we do not use a custom SigHandler -- we use the default one.
+    match unsafe { signal(SIGPIPE, SigDfl) } {
+        Ok(_) => Ok(()),
+        _ => Err(Error::from(ErrorKind::Other)),
     }
-    Ok(())
 }
 
 #[cfg(not(unix))]