diff --git a/ap/libc/glibc/glibc-2.23/string/strcasecmp.c b/ap/libc/glibc/glibc-2.23/string/strcasecmp.c
new file mode 100644
index 0000000..38372a5
--- /dev/null
+++ b/ap/libc/glibc/glibc-2.23/string/strcasecmp.c
@@ -0,0 +1,67 @@
+/* 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/>.  */
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+#include <ctype.h>
+#include <string.h>
+
+#ifndef _LIBC
+# define __strcasecmp strcasecmp
+# define TOLOWER(Ch) tolower (Ch)
+#else
+# include <locale/localeinfo.h>
+# ifdef USE_IN_EXTENDED_LOCALE_MODEL
+#  define __strcasecmp __strcasecmp_l
+# endif
+# define TOLOWER(Ch) __tolower_l ((Ch), loc)
+#endif
+
+#ifdef USE_IN_EXTENDED_LOCALE_MODEL
+# define LOCALE_PARAM , __locale_t loc
+#else
+# define LOCALE_PARAM
+#endif
+
+/* Compare S1 and S2, ignoring case, returning less than, equal to or
+   greater than zero if S1 is lexicographically less than,
+   equal to or greater than S2.  */
+int
+__strcasecmp (const char *s1, const char *s2 LOCALE_PARAM)
+{
+#if defined _LIBC && !defined USE_IN_EXTENDED_LOCALE_MODEL
+  __locale_t loc = _NL_CURRENT_LOCALE;
+#endif
+  const unsigned char *p1 = (const unsigned char *) s1;
+  const unsigned char *p2 = (const unsigned char *) s2;
+  int result;
+
+  if (p1 == p2)
+    return 0;
+
+  while ((result = TOLOWER (*p1) - TOLOWER (*p2++)) == 0)
+    if (*p1++ == '\0')
+      break;
+
+  return result;
+}
+#ifndef __strcasecmp
+libc_hidden_def (__strcasecmp)
+weak_alias (__strcasecmp, strcasecmp)
+#endif