std: Remove deprecated/unstable num functionality

This commit removes all the old casting/generic traits from `std::num` that are
no longer in use by the standard library. This additionally removes the old
`strconv` module which has not seen much use in quite a long time. All generic
functionality has been supplanted with traits in the `num` crate and the
`strconv` module is supplanted with the [rust-strconv crate][rust-strconv].

[rust-strconv]: https://github.com/lifthrasiir/rust-strconv

This is a breaking change due to the removal of these deprecated crates, and the
alternative crates are listed above.

[breaking-change]

1 files changed, 3 insertions, 6 deletions

diff --git a/src/libstd/time/duration.rs b/src/libstd/time/duration.rs
index 9b79b483b28..636a0dd697a 100644
--- a/src/libstd/time/duration.rs
+++ b/src/libstd/time/duration.rs
@@ -12,13 +12,10 @@
 
 #![unstable(feature = "std_misc")]
 
+use prelude::v1::*;
+
 use {fmt, i64};
-use ops::{Add, Sub, Mul, Div, Neg, FnOnce};
-use option::Option;
-use option::Option::{Some, None};
-#[allow(deprecated)] // Int
-use num::Int;
-use result::Result::Ok;
+use ops::{Add, Sub, Mul, Div, Neg};
 
 /// The number of nanoseconds in a microsecond.
 const NANOS_PER_MICRO: i32 = 1000;