extend stdlib to allow import of more packages (#1099)

* stdlib: extend stdlib to allow import of more packages

src/sync/map.go

@@ -42,3 +42,18 @@ func (m *Map) Store(key, value interface{}) {
 	}
 	m.m[key] = value
 }
+
+func (m *Map) Range(f func(key, value interface{}) bool) {
+	m.lock.Lock()
+	defer m.lock.Unlock()
+
+	if m.m == nil {
+		return
+	}
+
+	for k, v := range m.m {
+		if !f(k, v) {
+			break
+		}
+	}
+}

src/sync/mutex.go

@@ -74,3 +74,14 @@ type Locker interface {
 	Lock()
 	Unlock()
 }
+
+// RLocker returns a Locker interface that implements
+// the Lock and Unlock methods by calling rw.RLock and rw.RUnlock.
+func (rw *RWMutex) RLocker() Locker {
+	return (*rlocker)(rw)
+}
+
+type rlocker RWMutex
+
+func (r *rlocker) Lock()   { (*RWMutex)(r).RLock() }
+func (r *rlocker) Unlock() { (*RWMutex)(r).RUnlock() }