diff --git a/ap/libc/glibc/glibc-2.23/string/strings.h b/ap/libc/glibc/glibc-2.23/string/strings.h
new file mode 100644
index 0000000..e372a33
--- /dev/null
+++ b/ap/libc/glibc/glibc-2.23/string/strings.h
@@ -0,0 +1,139 @@
+/* Copyright (C) 1991-2016 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   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/>.  */
+
+#ifndef	_STRINGS_H
+#define	_STRINGS_H	1
+
+/* We don't need and should not read this file if <string.h> was already
+   read. The one exception being that if __USE_MISC isn't defined, then
+   these aren't defined in string.h, so we need to define them here.  */
+#if !defined _STRING_H || !defined __USE_MISC
+
+# include <features.h>
+# define __need_size_t
+# include <stddef.h>
+
+/* Tell the caller that we provide correct C++ prototypes.  */
+# if defined __cplusplus && __GNUC_PREREQ (4, 4)
+#  define __CORRECT_ISO_CPP_STRINGS_H_PROTO
+# endif
+
+__BEGIN_DECLS
+
+# if defined __USE_MISC || !defined __USE_XOPEN2K8
+/* Compare N bytes of S1 and S2 (same as memcmp).  */
+extern int bcmp (const void *__s1, const void *__s2, size_t __n)
+     __THROW __attribute_pure__;
+
+/* Copy N bytes of SRC to DEST (like memmove, but args reversed).  */
+extern void bcopy (const void *__src, void *__dest, size_t __n) __THROW;
+
+/* Set N bytes of S to 0.  */
+extern void bzero (void *__s, size_t __n) __THROW;
+
+/* Find the first occurrence of C in S (same as strchr).  */
+#  ifdef __CORRECT_ISO_CPP_STRINGS_H_PROTO
+extern "C++"
+{
+extern char *index (char *__s, int __c)
+     __THROW __asm ("index") __attribute_pure__ __nonnull ((1));
+extern const char *index (const char *__s, int __c)
+     __THROW __asm ("index") __attribute_pure__ __nonnull ((1));
+
+#   if defined __OPTIMIZE__ && !defined __CORRECT_ISO_CPP_STRING_H_PROTO
+__extern_always_inline char *
+index (char *__s, int __c) __THROW
+{
+  return __builtin_index (__s, __c);
+}
+
+__extern_always_inline const char *
+index (const char *__s, int __c) __THROW
+{
+  return __builtin_index (__s, __c);
+}
+#   endif
+}
+#  else
+extern char *index (const char *__s, int __c)
+     __THROW __attribute_pure__ __nonnull ((1));
+#  endif
+
+/* Find the last occurrence of C in S (same as strrchr).  */
+#  ifdef __CORRECT_ISO_CPP_STRINGS_H_PROTO
+extern "C++"
+{
+extern char *rindex (char *__s, int __c)
+     __THROW __asm ("rindex") __attribute_pure__ __nonnull ((1));
+extern const char *rindex (const char *__s, int __c)
+     __THROW __asm ("rindex") __attribute_pure__ __nonnull ((1));
+
+#   if defined __OPTIMIZE__ && !defined __CORRECT_ISO_CPP_STRING_H_PROTO
+__extern_always_inline char *
+rindex (char *__s, int __c) __THROW
+{
+  return __builtin_rindex (__s, __c);
+}
+
+__extern_always_inline const char *
+rindex (const char *__s, int __c) __THROW
+{
+  return __builtin_rindex (__s, __c);
+}
+#   endif
+}
+#  else
+extern char *rindex (const char *__s, int __c)
+     __THROW __attribute_pure__ __nonnull ((1));
+#  endif
+# endif
+
+#if defined __USE_MISC || !defined __USE_XOPEN2K8 || defined __USE_XOPEN2K8XSI
+/* Return the position of the first bit set in I, or 0 if none are set.
+   The least-significant bit is position 1, the most-significant 32.  */
+extern int ffs (int __i) __THROW __attribute__ ((const));
+#endif
+
+/* Compare S1 and S2, ignoring case.  */
+extern int strcasecmp (const char *__s1, const char *__s2)
+     __THROW __attribute_pure__;
+
+/* Compare no more than N chars of S1 and S2, ignoring case.  */
+extern int strncasecmp (const char *__s1, const char *__s2, size_t __n)
+     __THROW __attribute_pure__;
+
+#ifdef	__USE_XOPEN2K8
+/* The following functions are equivalent to the both above but they
+   take the locale they use for the collation as an extra argument.
+   This is not standardsized but something like will come.  */
+# include <xlocale.h>
+
+/* Again versions of a few functions which use the given locale instead
+   of the global one.  */
+extern int strcasecmp_l (const char *__s1, const char *__s2, __locale_t __loc)
+     __THROW __attribute_pure__ __nonnull ((1, 2, 3));
+
+extern int strncasecmp_l (const char *__s1, const char *__s2,
+			  size_t __n, __locale_t __loc)
+     __THROW __attribute_pure__ __nonnull ((1, 2, 4));
+#endif
+
+__END_DECLS
+
+#endif	/* string.h  */
+
+#endif	/* strings.h  */