libc: remove stddef.h which is provided by the compiler

Jira: ZEP-733
Change-Id: I26ba720377826bfa662c61e46c0358f05218524b
Signed-off-by: Anas Nashif <anas.nashif@intel.com>

lib/libc/minimal/include/stddef.h

@@ -1,36 +0,0 @@
-/* stddef.h */
-
-/*
- * Copyright (c) 2014 Wind River Systems, Inc.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-#ifndef __INC_stddef_h__
-#define __INC_stddef_h__
-
-#include <bits/null.h>
-#include <bits/size_t.h>
-
-#if !defined(__ptrdiff_t_defined)
-#define __ptrdiff_t_defined
-typedef int  ptrdiff_t;
-#endif
-
-#if defined(__GNUC__)
-#define offsetof(type, member)  __builtin_offsetof(type, member)
-#else
-#define offsetof(type, member) ((size_t) (&((type *) NULL)->member))
-#endif
-
-#endif /* __INC_stddef_h__ */