Remove the getaddrinfo mutex, but put mutex around winsock initialization.

runtime/bin/socket_win.cc

Index: runtime/bin/socket_win.cc
diff --git a/runtime/bin/socket_win.cc b/runtime/bin/socket_win.cc
index debff6b3f5f9ad270876c24dd9f7a50f1cd7c89f..7c27fde29cc6d64e71a6f62f6e2f255710db8c98 100644
--- a/runtime/bin/socket_win.cc
+++ b/runtime/bin/socket_win.cc
@@ -46,8 +46,11 @@ bool Socket::FormatNumericAddress(RawAddr* addr, char* address, int len) {
 }
 
 
+static Mutex* init_mutex = new Mutex();
+static bool socket_initialized = false;
+
 bool Socket::Initialize() {
-  static bool socket_initialized = false;
+  MutexLocker lock(init_mutex);
   if (socket_initialized) return true;
   int err;
   WSADATA winsock_data;
@@ -219,15 +222,11 @@ intptr_t ServerSocket::Accept(intptr_t fd) {
 }
 
 
-static Mutex* getaddrinfo_mutex = new Mutex();
 AddressList<SocketAddress>* Socket::LookupAddress(const char* host,
                                                   int type,
                                                   OSError** os_error) {
   Initialize();
 
-  // getaddrinfo is not thread-safe on Windows. Use a mutex to get around it.
-  MutexLocker locker(getaddrinfo_mutex);
-
   // Perform a name lookup for a host name.
   struct addrinfo hints;
   memset(&hints, 0, sizeof(hints));