Fuchsia: resolve executable name, fetch environment vars

runtime/bin/file_fuchsia.cc

 // 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.
 
 #include "platform/globals.h"
 #if defined(TARGET_OS_FUCHSIA)
 
 #include "bin/file.h"
 
 #include <errno.h>      // NOLINT
@@ skipping 335 matching lines @@
   return target_name;
 }
 
 
 bool File::IsAbsolutePath(const char* pathname) {
   return ((pathname != NULL) && (pathname[0] == '/'));
 }
 
 
 const char* File::GetCanonicalPath(const char* pathname) {
+  // TODO(MG-425): realpath() is not implemented.
+#if 0
   char* abs_path = NULL;
   if (pathname != NULL) {
     char* resolved_path = DartUtils::ScopedCString(PATH_MAX + 1);
     ASSERT(resolved_path != NULL);
     do {
       abs_path = realpath(pathname, resolved_path);
     } while ((abs_path == NULL) && (errno == EINTR));
     ASSERT((abs_path == NULL) || IsAbsolutePath(abs_path));
     ASSERT((abs_path == NULL) || (abs_path == resolved_path));
   }
   return abs_path;
+#else
+  return pathname;
+#endif
 }
 
 
 const char* File::PathSeparator() {
   return "/";
 }
 
 
 const char* File::StringEscapedPathSeparator() {
   return "/";
@@ skipping 60 matching lines @@
   return ((file_1_info.st_ino == file_2_info.st_ino) &&
           (file_1_info.st_dev == file_2_info.st_dev))
              ? File::kIdentical
              : File::kDifferent;
 }
 
 }  // namespace bin
 }  // namespace dart
 
 #endif  // defined(TARGET_OS_FUCHSIA)