Pretty-printing uses CRLF on Windows. Closes #14808.

Author: tamird

Diff for: src/libsyntax/print/pp.rs

@@ -507,8 +507,14 @@ impl<'a> Printer<'a> {
         }
     }
     pub fn print_newline(&mut self, amount: isize) -> io::Result<()> {
+        #[cfg(windows)]
+        const NEWLINE: &'static str = "\r\n";
+
+        #[cfg(not(windows))]
+        const NEWLINE: &'static str = "\n";
+
         debug!("NEWLINE {}", amount);
-        let ret = write!(self.out, "\n");
+        let ret = self.out.write_all(NEWLINE.as_bytes());
         self.pending_indentation = 0;
         self.indent(amount);
         return ret;