Fix no_std errors

Cargo.toml

@@ -16,12 +16,15 @@ categories = ["algorithms"]
 [features]
 default = ["std"]
 nightly = ["i128_support"]
-std = []
+std = ["rand_core/std"]
 i128_support = ["rand_core/i128_support"]
 
 [dependencies]
 libc = "0.2"
-rand_core = { path = 'rand_core' }
+
+[dependencies.rand_core]
+path = 'rand_core'
+default-features = false
 
 [target.'cfg(target_os = "fuchsia")'.dependencies]
 fuchsia-zircon = "^0.2.1"

benches/generators.rs

@@ -79,7 +79,7 @@ macro_rules! init_gen {
     ($fnn:ident, $gen:ident) => {
         #[bench]
         fn $fnn(b: &mut Bencher) {
-            let mut rng = OsRng::new().unwrap();
+            let mut rng = XorShiftRng::new().unwrap();
             b.iter(|| {
                 black_box($gen::from_rng(&mut rng).unwrap());
             });

src/jitter_rng.rs

@@ -655,6 +655,7 @@ impl JitterRng {
     /// #     try_main().unwrap();
     /// # }
     /// ```
+    #[cfg(feature="std")]
     pub fn timer_stats(&mut self, var_rounds: bool) -> i64 {
         let time = get_nstime();
         self.memaccess(var_rounds);