auto merge of #13115 : huonw/rust/rand-errors, r=alexcrichton

move errno -> IoError converter into std, bubble up OSRng errors

Also adds a general errno -> `~str` converter to `std::os`, and makes the failure messages for the things using `OSRng` (e.g. (transitively) the task-local RNG, meaning hashmap initialisation failures aren't such a black box).

1 files changed, 2 insertions, 2 deletions

diff --git a/src/libcollections/deque.rs b/src/libcollections/deque.rs
index 9c1427d0225..6c1391e7ca8 100644
--- a/src/libcollections/deque.rs
+++ b/src/libcollections/deque.rs
@@ -52,7 +52,7 @@ pub mod bench {
                                                   map: &mut M,
                                                   bh: &mut BenchHarness) {
         // setup
-        let mut rng = rand::XorShiftRng::new();
+        let mut rng = rand::weak_rng();
 
         map.clear();
         for _ in range(0, n) {
@@ -89,7 +89,7 @@ pub mod bench {
                                                 map: &mut M,
                                                 bh: &mut BenchHarness) {
         // setup
-        let mut rng = rand::XorShiftRng::new();
+        let mut rng = rand::weak_rng();
         let mut keys = slice::from_fn(n, |_| rng.gen::<uint>() % n);
 
         for k in keys.iter() {