Revert new OS and CC detection and related changes since r15923.

src/isolate-inl.h

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 21 matching lines @@
 
 #include "debug.h"
 
 namespace v8 {
 namespace internal {
 
 
 SaveContext::SaveContext(Isolate* isolate) : prev_(isolate->save_context()) {
   if (isolate->context() != NULL) {
     context_ = Handle<Context>(isolate->context());
-#if V8_GNUC_PREREQ(4, 1) && !V8_GNUC_PREREQ(4, 3)
+#if __GNUC_VERSION__ >= 40100 && __GNUC_VERSION__ < 40300
     dummy_ = Handle<Context>(isolate->context());
 #endif
   }
   isolate->set_save_context(this);
 
   c_entry_fp_ = isolate->c_entry_fp(isolate->thread_local_top());
 }
 
 
 bool Isolate::IsDebuggerActive() {
@@ skipping 11 matching lines @@
   return debug()->has_break_points();
 #else
   return false;
 #endif
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_ISOLATE_INL_H_