Revert r43217, r43215, r43208, r43207, and r43202.

runtime/bin/platform_linux.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_LINUX)
 
 #include "bin/platform.h"
 
 #include <signal.h>  // NOLINT
@@ skipping 24 matching lines @@
 int Platform::NumberOfProcessors() {
   return sysconf(_SC_NPROCESSORS_ONLN);
 }
 
 
 const char* Platform::OperatingSystem() {
   return "linux";
 }
 
 
-const char* Platform::LibraryExtension() {
-  return "so";
-}
-
-
 bool Platform::LocalHostname(char *buffer, intptr_t buffer_length) {
   return gethostname(buffer, buffer_length) == 0;
 }
 
 
 char** Platform::Environment(intptr_t* count) {
   // Using environ directly is only safe as long as we do not
   // provide access to modifying environment variables.
   intptr_t i = 0;
   char** tmp = environ;
   while (*(tmp++) != NULL) i++;
   *count = i;
   char** result = new char*[i];
   for (intptr_t current = 0; current < i; current++) {
     result[current] = environ[current];
   }
   return result;
 }
 
 
 void Platform::FreeEnvironment(char** env, intptr_t count) {
   delete[] env;
 }
 
 }  // namespace bin
 }  // namespace dart
 
 #endif  // defined(TARGET_OS_LINUX)