rt: Remove sync::yield and sync::sleep

mk/rt.mk

@@ -35,7 +35,6 @@ define DEF_RUNTIME_TARGETS
 
 RUNTIME_CS_$(1) := \
               rt/sync/timer.cpp \
-              rt/sync/sync.cpp \
               rt/sync/lock_and_signal.cpp \
               rt/sync/rust_thread.cpp \
               rt/rust.cpp \

src/rt/sync/sync.cpp

@@ -1,20 +0,0 @@
-#include "../globals.h"
-#include "sync.h"
-
-void sync::yield() {
-#ifdef __APPLE__
-    pthread_yield_np();
-#elif __WIN32__
-    Sleep(1);
-#else
-    pthread_yield();
-#endif
-}
-
-void sync::sleep(size_t timeout_in_ms) {
-#ifdef __WIN32__
-    Sleep(timeout_in_ms);
-#else
-    usleep(timeout_in_ms * 1000);
-#endif
-}

src/rt/sync/sync.h

@@ -4,8 +4,6 @@
 
 class sync {
 public:
-    static void yield();
-    static void sleep(size_t timeout_in_ms);
     template <class T>
     static bool compare_and_swap(T *address,
         T oldValue, T newValue) {