seq: fix broken pipe on Busybox test

seq/seq.rs

@@ -9,6 +9,7 @@ extern crate getopts;
 extern crate libc;
 
 use std::cmp;
+use std::io;
 use std::os;
 
 #[path = "../common/util.rs"]
@@ -16,6 +17,20 @@ mod util;
 
 static NAME: &'static str = "seq";
 
+macro_rules! pipe_write(
+    ($($args:expr),+) => (
+        match write!(&mut io::stdout() as &mut Writer, $($args),+) {
+            Ok(_) => {}
+            Err(f) =>
+                if f.kind == io::BrokenPipe {
+                    return
+                } else {
+                    fail!("{}", f.to_str())
+                }
+        }
+    )
+)
+
 #[deriving(Clone)]
 struct SeqOptions {
     separator: String,
@@ -226,27 +241,27 @@ fn print_seq(first: f64, step: f64, last: f64, largest_dec: uint, separator: Str
         let before_dec = istr.as_slice().find('.').unwrap_or(ilen);
         if pad && before_dec < padding {
             for _ in range(0, padding - before_dec) {
-                print!("0");
+                pipe_write!("0");
             }
         }
-        print!("{}", istr);
+        pipe_write!("{}", istr);
         let mut idec = ilen - before_dec;
         if idec < largest_dec {
             if idec == 0 {
-                print!(".");
+                pipe_write!(".");
                 idec += 1;
             }
             for _ in range(idec, largest_dec) {
-                print!("0")
+                pipe_write!("0")
             }
         }
         i += 1;
         value = first + i as f64 * step;
         if !done_printing(value, step, last) {
-            print!("{:s}", separator);
+            pipe_write!("{:s}", separator);
         }
     }
     if (first >= last && step < 0f64) || (first <= last && step > 0f64) {
-        print!("{:s}", terminator);
+        pipe_write!("{:s}", terminator);
     }
 }