tail: add equivalent of stdin_is_pipe_or_fifo() for Windows

* add support to determine if stdin is readable on Windows

Cargo.lock

@@ -2939,6 +2939,7 @@ dependencies = [
  "notify",
  "uucore",
  "winapi 0.3.9",
+ "winapi-util",
 ]
 
 [[package]]

src/uu/tail/Cargo.toml

@@ -24,6 +24,7 @@ uucore = { version=">=0.0.11", package="uucore", path="../../uucore", features=[
 
 [target.'cfg(windows)'.dependencies]
 winapi = { version="0.3", features=["fileapi", "handleapi", "processthreadsapi", "synchapi", "winbase"] }
+winapi-util = { version= "0.1.5" }
 
 [target.'cfg(unix)'.dependencies]
 nix = { version = "0.24.1", default-features = false, features=["fs"] }

src/uu/tail/src/tail.rs

@@ -1435,10 +1435,13 @@ pub fn stdin_is_pipe_or_fifo() -> bool {
     {
         platform::stdin_is_pipe_or_fifo()
     }
-    // FIXME windows has GetFileType which can determine if the file is a pipe/FIFO
-    // so this check can also be performed
-    #[cfg(not(unix))]
-    false
+    #[cfg(windows)]
+    {
+        use winapi_util;
+        winapi_util::file::typ(winapi_util::HandleRef::stdin())
+            .map(|t| t.is_disk() || t.is_pipe())
+            .unwrap_or(false)
+    }
 }
 
 pub fn stdin_is_bad_fd() -> bool {

tests/by-util/test_tail.rs

@@ -11,7 +11,9 @@ extern crate tail;
 
 use crate::common::util::*;
 use std::char::from_digit;
-use std::io::{Read, Write};
+#[cfg(unix)]
+use std::io::Read;
+use std::io::Write;
 use std::process::Stdio;
 #[cfg(unix)]
 use std::thread::sleep;