Plumbing though mode parameter to open, since fusefs can make use of it.

native_client_sdk/src/libraries/nacl_io/devfs/dev_fs.h

Index: native_client_sdk/src/libraries/nacl_io/devfs/dev_fs.h
diff --git a/native_client_sdk/src/libraries/nacl_io/devfs/dev_fs.h b/native_client_sdk/src/libraries/nacl_io/devfs/dev_fs.h
index 9d20b6bd1bb375ba8b32973a34a51a8f4b3a5381..872f77ef9d858eb1e323b6f00dc9f3b1970fd57c 100644
--- a/native_client_sdk/src/libraries/nacl_io/devfs/dev_fs.h
+++ b/native_client_sdk/src/libraries/nacl_io/devfs/dev_fs.h
@@ -14,7 +14,8 @@ class Node;
 
 class DevFs : public Filesystem {
  public:
-  virtual Error Open(const Path& path, int open_flags, ScopedNode* out_node);
+  virtual Error OpenWithMode(const Path& path, int open_flags, mode_t mode,
+                             ScopedNode* out_node);
   virtual Error Unlink(const Path& path);
   virtual Error Mkdir(const Path& path, int permissions);
   virtual Error Rmdir(const Path& path);