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Also convert a number of `static mut` to just a plain old `static` and remove
some unsafe blocks.

src/libstd/rt/util.rs

@@ -41,8 +41,8 @@ pub fn limit_thread_creation_due_to_osx_and_valgrind() -> bool {
 }
 
 pub fn min_stack() -> uint {
-    static mut MIN: atomic::AtomicUint = atomic::INIT_ATOMIC_UINT;
-    match unsafe { MIN.load(atomic::SeqCst) } {
+    static MIN: atomic::AtomicUint = atomic::INIT_ATOMIC_UINT;
+    match MIN.load(atomic::SeqCst) {
         0 => {}
         n => return n - 1,
     }
@@ -50,7 +50,7 @@ pub fn min_stack() -> uint {
     let amt = amt.unwrap_or(2 * 1024 * 1024);
     // 0 is our sentinel value, so ensure that we'll never see 0 after
     // initialization has run
-    unsafe { MIN.store(amt + 1, atomic::SeqCst); }
+    MIN.store(amt + 1, atomic::SeqCst);
     return amt;
 }