remove is_terminal function, same functionality exists in rust standard library

src/unix.rs

@@ -2,7 +2,6 @@ use std::ffi::{c_int, c_uint, c_ulong, c_ushort};
 use std::io;
 
 unsafe extern "C" {
-    fn isatty(fd: c_int) -> c_int;
     fn ioctl(fd: c_int, request: c_ulong, argp: *mut u8) -> c_int;
     fn tcgetattr(fd: c_int, termios_p: *mut Termios) -> c_int;
     fn tcsetattr(fd: c_int, optional_actions: c_int, termios: *mut Termios) -> c_int;
@@ -46,12 +45,6 @@ struct Termios {
     cc: [u8; NCCS],
 }
 
-/// Checks if stdout is a terminal
-#[must_use]
-pub fn is_terminal() -> bool {
-    unsafe { isatty(1) != 0 }
-}
-
 /// Enables ANSI support on Windows terminals
 ///
 /// ANSI is on by default on *nix machines but still exists on them for simpler usage

src/windows.rs

@@ -36,19 +36,6 @@ struct ConsoleScreenBufferInfo {
     dwMaximumWindowSizeY: u16,
 }
 
-/// Checks if stdout is a terminal
-#[must_use]
-pub fn is_terminal() -> bool {
-    let handle = get_std_handle(STD_OUTPUT_HANDLE);
-    match handle {
-        Ok(handle) => {
-            let mut dwMode = 0;
-            unsafe { GetConsoleMode(handle, &mut dwMode) != 0 }
-        }
-        _ => false,
-    }
-}
-
 /// Enables ANSI support on Windows terminals
 ///
 /// ANSI is on by default on *nix machines but still exists on them for simpler usage