diff --git a/ap/libc/glibc/glibc-2.23/string/test-string.h b/ap/libc/glibc/glibc-2.23/string/test-string.h
new file mode 100644
index 0000000..728a7c2
--- /dev/null
+++ b/ap/libc/glibc/glibc-2.23/string/test-string.h
@@ -0,0 +1,199 @@
+/* Test and measure string and memory functions.
+   Copyright (C) 1999-2016 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Written by Jakub Jelinek <jakub@redhat.com>, 1999.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <sys/cdefs.h>
+
+typedef struct
+{
+  const char *name;
+  void (*fn) (void);
+  long test;
+} impl_t;
+extern impl_t __start_impls[], __stop_impls[];
+
+#define IMPL(name, test) \
+  impl_t tst_ ## name							\
+  __attribute__ ((section ("impls"), aligned (sizeof (void *))))	\
+       = { __STRING (name), (void (*) (void))name, test };
+
+#ifdef TEST_MAIN
+
+#ifndef _GNU_SOURCE
+#define _GNU_SOURCE
+#endif
+
+#undef __USE_STRING_INLINES
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/mman.h>
+#include <sys/param.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <error.h>
+#include <errno.h>
+#include <time.h>
+#include <ifunc-impl-list.h>
+#define GL(x) _##x
+#define GLRO(x) _##x
+
+
+# define TEST_FUNCTION test_main ()
+# define TIMEOUT (4 * 60)
+# define OPT_ITERATIONS 10000
+# define OPT_RANDOM 10001
+# define OPT_SEED 10002
+
+unsigned char *buf1, *buf2;
+int ret, do_srandom;
+unsigned int seed;
+size_t page_size;
+
+# ifndef ITERATIONS
+size_t iterations = 100000;
+#  define ITERATIONS_OPTIONS \
+  { "iterations", required_argument, NULL, OPT_ITERATIONS },
+#  define ITERATIONS_PROCESS \
+  case OPT_ITERATIONS:				\
+    iterations = strtoul (optarg, NULL, 0);	\
+    break;
+#  define ITERATIONS iterations
+# else
+#  define ITERATIONS_OPTIONS
+#  define ITERATIONS_PROCESS
+# endif
+
+# define CMDLINE_OPTIONS ITERATIONS_OPTIONS \
+  { "random", no_argument, NULL, OPT_RANDOM },	\
+  { "seed", required_argument, NULL, OPT_SEED },
+# define CMDLINE_PROCESS ITERATIONS_PROCESS \
+  case OPT_RANDOM:							\
+    {									\
+      int fdr = open ("/dev/urandom", O_RDONLY);			\
+									\
+      if (fdr < 0 || read (fdr, &seed, sizeof(seed)) != sizeof (seed))	\
+	seed = time (NULL);						\
+      if (fdr >= 0)							\
+	close (fdr);							\
+      do_srandom = 1;							\
+      break;								\
+    }									\
+									\
+  case OPT_SEED:							\
+    seed = strtoul (optarg, NULL, 0);					\
+    do_srandom = 1;							\
+    break;
+
+#define CALL(impl, ...)	\
+  (* (proto_t) (impl)->fn) (__VA_ARGS__)
+
+#ifdef TEST_NAME
+/* Increase size of FUNC_LIST if assert is triggered at run-time.  */
+static struct libc_ifunc_impl func_list[32];
+static int func_count;
+static int impl_count = -1;
+static impl_t *impl_array;
+
+# define FOR_EACH_IMPL(impl, notall) \
+  impl_t *impl;								\
+  int count;								\
+  if (impl_count == -1)							\
+    {									\
+      impl_count = 0;							\
+      if (func_count != 0)						\
+	{								\
+	  int f;							\
+	  impl_t *skip = NULL, *a;					\
+	  for (impl = __start_impls; impl < __stop_impls; ++impl)	\
+	    if (strcmp (impl->name, TEST_NAME) == 0)			\
+	      skip = impl;						\
+	    else							\
+	      impl_count++;						\
+	  a = impl_array = malloc ((impl_count + func_count) *		\
+				   sizeof (impl_t));			\
+	  for (impl = __start_impls; impl < __stop_impls; ++impl)	\
+	    if (impl != skip)						\
+	      *a++ = *impl;						\
+	  for (f = 0; f < func_count; f++)				\
+	    if (func_list[f].usable)					\
+	      {								\
+		a->name = func_list[f].name;				\
+		a->fn = func_list[f].fn;				\
+		a->test = 1;						\
+		a++;							\
+	      }								\
+	  impl_count = a - impl_array;					\
+	}								\
+      else								\
+        {								\
+	  impl_count = __stop_impls - __start_impls;			\
+	  impl_array = __start_impls;					\
+        }								\
+    }									\
+  impl = impl_array;							\
+  for (count = 0; count < impl_count; ++count, ++impl)			\
+    if (!notall || impl->test)
+#else
+# define FOR_EACH_IMPL(impl, notall) \
+  for (impl_t *impl = __start_impls; impl < __stop_impls; ++impl)	\
+    if (!notall || impl->test)
+#endif
+
+#ifndef BUF1PAGES
+# define BUF1PAGES 1
+#endif
+
+static void
+test_init (void)
+{
+#ifdef TEST_NAME
+  func_count = __libc_ifunc_impl_list (TEST_NAME, func_list,
+				       (sizeof func_list
+					/ sizeof func_list[0]));
+#endif
+
+  page_size = 2 * getpagesize ();
+#ifdef MIN_PAGE_SIZE
+  if (page_size < MIN_PAGE_SIZE)
+    page_size = MIN_PAGE_SIZE;
+#endif
+  buf1 = mmap (0, (BUF1PAGES + 1) * page_size, PROT_READ | PROT_WRITE,
+	       MAP_PRIVATE | MAP_ANON, -1, 0);
+  if (buf1 == MAP_FAILED)
+    error (EXIT_FAILURE, errno, "mmap failed");
+  if (mprotect (buf1 + BUF1PAGES * page_size, page_size, PROT_NONE))
+    error (EXIT_FAILURE, errno, "mprotect failed");
+  buf2 = mmap (0, 2 * page_size, PROT_READ | PROT_WRITE,
+	       MAP_PRIVATE | MAP_ANON, -1, 0);
+  if (buf2 == MAP_FAILED)
+    error (EXIT_FAILURE, errno, "mmap failed");
+  if (mprotect (buf2 + page_size, page_size, PROT_NONE))
+    error (EXIT_FAILURE, errno, "mprotect failed");
+  if (do_srandom)
+    {
+      printf ("Setting seed to 0x%x\n", seed);
+      srandom (seed);
+    }
+
+  memset (buf1, 0xa5, BUF1PAGES * page_size);
+  memset (buf2, 0x5a, page_size);
+}
+
+#endif