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, 1 insertions, 1 deletions

diff --git a/src/libstd/rt/task.rs b/src/libstd/rt/task.rs
index d9700ea9980..0f90135512c 100644
--- a/src/libstd/rt/task.rs
+++ b/src/libstd/rt/task.rs
@@ -435,7 +435,7 @@ mod test {
     #[test]
     fn rng() {
         use rand::{StdRng, Rng};
-        let mut r = StdRng::new();
+        let mut r = StdRng::new().unwrap();
         let _ = r.next_u32();
     }