Fix native extension lookup

runtime/bin/utils_macos.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "platform/globals.h"
 #if defined(TARGET_OS_MACOS)
 
 #include <errno.h>  // NOLINT
 #include <mach/clock.h>  // NOLINT
 #include <mach/mach.h>  // NOLINT
@@ skipping 59 matching lines @@
 }
 
 
 char* StringUtils::Utf8ToConsoleString(
     char* utf8, intptr_t len, intptr_t* result_len) {
   UNIMPLEMENTED();
   return NULL;
 }
 
 
+char* StringUtils::StrNDup(const char* s, intptr_t n) {
+  return strndup(s, n);
+}
+
+
 bool ShellUtils::GetUtf8Argv(int argc, char** argv) {
   return false;
 }
 
 
 static mach_timebase_info_data_t timebase_info;
 
 
 void TimerUtils::InitOnce() {
   kern_return_t kr = mach_timebase_info(&timebase_info);
@@ skipping 64 matching lines @@
     ASSERT(errno == EINTR);
     // Copy remainder into requested and repeat.
     req = rem;
   }
 }
 
 }  // namespace bin
 }  // namespace dart
 
 #endif  // defined(TARGET_OS_MACOS)