Migrate from collections

src/sync/wait_condition.rs

@@ -1,5 +1,5 @@
 use alloc::arc::Arc;
-use collections::Vec;
+use alloc::Vec;
 use spin::{Mutex, RwLock};
 
 use context::{self, Context, SwitchResult};

src/sync/wait_map.rs

@@ -1,4 +1,4 @@
-use collections::BTreeMap;
+use alloc::BTreeMap;
 use core::mem;
 use spin::Mutex;
 

src/sync/wait_queue.rs

@@ -1,4 +1,4 @@
-use collections::vec_deque::VecDeque;
+use alloc::vec_deque::VecDeque;
 use spin::Mutex;
 
 use sync::WaitCondition;