1) Make Compatibility/Include the public include directory.

2) Add two PPI 

git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@5229 6f19259b-4bc3-4df7-8a09-765794883524

EdkCompatibilityPkg/Compatibility/Include/Ppi/ReadOnlyVariableThunkPresent.h

@@ -0,0 +1,28 @@
+/** @file
+  PPI published by the ReadOnlyVariable to ReadOnlyVariable2 or ReadOnlyVariable2 to ReadOnlyVariable
+  thunking PEIM to mark that such module has already been excuted.
+
+  This PPI is referenced in Edk2/EdkCompatibility/Compatibility/ReadOnlyVariable2ToReadOnlyVariable 
+  and Edk2/EdkCompatibility/Compatibility/ReadOnlyVariable2ToReadOnlyVariable.
+
+Copyright (c) 2006 - 2008, Intel Corporation. <BR>
+All rights reserved. This program and the accompanying materials
+are licensed and made available under the terms and conditions of the BSD License
+which accompanies this distribution.  The full text of the license may be found at
+http://opensource.org/licenses/bsd-license.php
+
+THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
+WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
+
+**/
+
+#ifndef _PEI_READONLY_VARIABLE_THUNK_PRESENT_H_
+#define _PEI_READONLY_VARIABLE_THUNK_PRESENT_H_
+
+#define PEI_READONLY_VARIABLE_THUNK_PRESENT_GUID  \
+  { 0xe84e9e0b, 0xb5dd, 0x4d08, { 0x9e, 0x46, 0x82, 0x1f, 0xf, 0x14, 0xe9, 0x1b } }
+
+extern EFI_GUID                     gPeiReadonlyVariableThunkPresentPpiGuid;
+
+#endif
+