Update gc branch to bleeding_edge revision 8862.

src/platform.h

Index: src/platform.h
diff --git a/src/platform.h b/src/platform.h
index 06adbe95da98fd6b420d8be69b294ad76c4b4077..6a8395775041209fd96cff65d6d943ffdce45e1d 100644
--- a/src/platform.h
+++ b/src/platform.h
@@ -207,6 +207,9 @@ class OS {
                         bool is_executable);
   static void Free(void* address, const size_t size);
 
+  // Mark code segments non-writable.
+  static void ProtectCode(void* address, const size_t size);
+
   // Assign memory as a guard page so that access will cause an exception.
   static void Guard(void* address, const size_t size);