Use 'libc' directly instead of through rustix (#26)

Cargo.toml

@@ -15,8 +15,8 @@ edition = "2018"
 include = ["src", "build.rs", "Cargo.toml", "COPYRIGHT", "LICENSE*", "/*.md"]
 rust-version = "1.63"
 
-[target.'cfg(not(any(windows, target_os = "hermit", target_os = "unknown")))'.dependencies]
-rustix = { version = "0.38.0", features = ["termios"] }
+[target.'cfg(any(unix, target_os = "wasi"))'.dependencies]
+libc = "0.2"
 
 [target.'cfg(target_os = "hermit")'.dependencies]
 hermit-abi = "0.3.0"
@@ -33,6 +33,7 @@ features = [
 atty = "0.2.14"
 
 [target.'cfg(any(unix, target_os = "wasi"))'.dev-dependencies]
+rustix = { version = "0.38.0", features = ["termios"] }
 libc = "0.2.110"
 
 [target.'cfg(not(any(windows, target_os = "hermit", target_os = "unknown")))'.dev-dependencies]

src/lib.rs

@@ -25,10 +25,19 @@
 //!
 //! [`isatty`]: https://man7.org/linux/man-pages/man3/isatty.3.html
 
-#![cfg_attr(unix, no_std)]
-
-#[cfg(not(any(windows, target_os = "hermit", target_os = "unknown")))]
-use rustix::fd::AsFd;
+#![cfg_attr(
+    not(any(
+        unix,
+        windows,
+        target_os = "wasi",
+        target_os = "hermit",
+        target_os = "unknown"
+    )),
+    no_std
+)]
+
+#[cfg(any(unix, target_os = "wasi"))]
+use std::os::fd::{AsFd, AsRawFd};
 #[cfg(target_os = "hermit")]
 use std::os::hermit::io::AsFd;
 #[cfg(windows)]
@@ -75,7 +84,7 @@ impl<Stream: AsFd> IsTerminal for Stream {
     fn is_terminal(&self) -> bool {
         #[cfg(any(unix, target_os = "wasi"))]
         {
-            rustix::termios::isatty(self)
+            unsafe { libc::isatty(self.as_fd().as_raw_fd()) == 1 }
         }
 
         #[cfg(target_os = "hermit")]