Added no_std support

src/stdlib.rs

@@ -0,0 +1,23 @@
+#[cfg(feature = "no_stdlib")]
+mod inner {
+    pub use core::{
+        any, arch, array, ascii, cell, char, clone, cmp, convert, default, f32, f64, ffi, fmt,
+        future, hash, hint, i128, i16, i32, i64, i8, isize, iter, marker, mem, num, ops, option,
+        panic, pin, prelude, ptr, result, slice, str, task, time, u128, u16, u32, u64, u8, usize,
+    };
+
+    pub use alloc::{borrow, boxed, format, string, sync, vec};
+
+    pub use core_error as error;
+
+    pub mod collections {
+        pub use hashbrown::HashMap;
+    }
+}
+
+#[cfg(not(feature = "no_stdlib"))]
+mod inner {
+    pub use std::*;
+}
+
+pub use self::inner::*;