strnlen is not always available.

runtime/vm/os_win.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 "vm/globals.h"
 #if defined(TARGET_OS_WINDOWS)
 
 #include "vm/os.h"
 
 #include <malloc.h>  // NOLINT
@@ skipping 241 matching lines @@
   }
   char* result = reinterpret_cast<char*>(malloc(len + 1));
   if (result == NULL) {
     return NULL;
   }
   result[len] = '\0';
   return reinterpret_cast<char*>(memmove(result, s, len));
 }
 
 
+intptr_t OS::StrNDup(const char* s, intptr_t n) {

[zra, 2016/05/17 19:39:27]

StrNLen?

+  return strnlen(s, n);
+}
+
+
 void OS::Print(const char* format, ...) {
   va_list args;
   va_start(args, format);
   VFPrint(stdout, format, args);
   va_end(args);
 }
 
 
 void OS::VFPrint(FILE* stream, const char* format, va_list args) {
   vfprintf(stream, format, args);
@@ skipping 147 matching lines @@
   // TODO(zra): Remove once VM shuts down cleanly.
   private_flag_windows_run_tls_destructors = false;
   // On Windows we use ExitProcess so that threads can't clobber the exit_code.
   // See: https://code.google.com/p/nativeclient/issues/detail?id=2870
   ::ExitProcess(code);
 }
 
 }  // namespace dart
 
 #endif  // defined(TARGET_OS_WINDOWS)