vpx_mem: remove REPLACE_BUILTIN_FUNCTIONS

vestigial. there are other ways to achieve this.

Change-Id: Ie977ce952527e596479df3084f331b694a682e39

vpx_mem/vpx_mem.h

diff --git a/vpx_mem/vpx_mem.h b/vpx_mem/vpx_mem.h
index f6876d6..d404efa 100644
--- a/vpx_mem/vpx_mem.h
+++ b/vpx_mem/vpx_mem.h
@@ -17,11 +17,6 @@
 # include <lddk.h>
 #endif
 
-#ifndef REPLACE_BUILTIN_FUNCTIONS
-# define REPLACE_BUILTIN_FUNCTIONS 0  /* replace builtin functions with their
-vpx_ equivalents */
-#endif
-
 #include <stdlib.h>
 #include <stddef.h>
 
@@ -42,24 +37,6 @@
 #endif
   void *vpx_memmove(void *dest, const void *src, size_t count);
 
-  /* some defines for backward compatibility */
-#define DMEM_GENERAL 0
-
-// (*)<
-
-#if REPLACE_BUILTIN_FUNCTIONS
-# ifndef __VPX_MEM_C__
-#  define memalign vpx_memalign
-#  define malloc   vpx_malloc
-#  define calloc   vpx_calloc
-#  define realloc  vpx_realloc
-#  define free     vpx_free
-#  define memcpy   vpx_memcpy
-#  define memmove  vpx_memmove
-#  define memset   vpx_memset
-# endif
-#endif
-
 #ifndef __VPX_MEM_C__
 # include <string.h>
 # define vpx_memcpy  memcpy