Fuchsia: Build standalone VM. Make it run "Hello, World!".

runtime/platform/utils_fuchsia.h

 // Copyright (c) 2016, 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.
 
 #ifndef PLATFORM_UTILS_FUCHSIA_H_
 #define PLATFORM_UTILS_FUCHSIA_H_
 
 #include "platform/assert.h"
 
 namespace dart {
@@ skipping 50 matching lines @@
 }
 
 
 inline uint64_t Utils::HostToLittleEndian64(uint64_t value) {
   UNIMPLEMENTED();
   return 0;
 }
 
 
 inline char* Utils::StrError(int err, char* buffer, size_t bufsize) {
-  UNIMPLEMENTED();
-  return NULL;
+  snprintf(buffer, bufsize, "errno = %d", err);
+  return buffer;
 }
 
 }  // namespace dart
 
 #endif  // PLATFORM_UTILS_FUCHSIA_H_