Add helper functions and files for gpt tests.

src/platform/vboot_reference/common/include/utility.h

 /* Copyright (c) 2010 The Chromium OS Authors. All rights reserved.
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 /* Helper functions/wrappers for memory allocations, manipulation and
  * comparison.
  */
 
 #ifndef VBOOT_REFERENCE_UTILITY_H_
@@ skipping 22 matching lines @@
 #define Min(a, b) (((a) < (b)) ? (a) : (b))
 
 /* Allocate [size] bytes and return a pointer to the allocated memory. Abort
  * on error.
  */
 void* Malloc(size_t size);
 
 /* Free memory pointed by [ptr] previously allocated by Malloc(). */
 void Free(void* ptr);
 
+/* Compare [n] bytes in [src1] and [src2]
+ * Returns an integer less than, equal to, or greater than zero if the first [n]
+ * bytes of [src1] is found, respectively, to be less than, to match, or be
+ * greater than the first n bytes of [src2]. */
+int Memcmp(const void* src1, const void* src2, size_t n);
+
 /* Copy [n] bytes from [src] to [dest]. */
 void* Memcpy(void* dest, const void* src, size_t n);
 
 /* Set [n] bytes starting at [s] to [c]. */
 void* Memset(void *dest, const uint8_t c, size_t n);
 
 /* Compare [n] bytes starting at [s1] with [s2] and return 0 if they match,
  * 1 if they don't. Time taken to perform the comparison is only dependent on
  * [n] and not on the relationship of the match between [s1] and [s2].
  */
@@ skipping 20 matching lines @@
  * data from [src] into the buffer encapsulated in state [state].
  * On success, return [src] and update [state].
  * On failure, return NULL, set remaining_len in state to -1.
  *
  * Useful for iterating through a structure to populate a binary blob. After the
  * first failure (buffer overrun), successive calls will always fail.
  */
 const void* StatefulMemcpy_r(MemcpyState* state, const void* src, uint64_t len);
 
 #endif  /* VBOOT_REFERENCE_UTILITY_H_ */