diff --git a/ap/libc/glibc/glibc-2.23/string/argz-insert.c b/ap/libc/glibc/glibc-2.23/string/argz-insert.c
new file mode 100644
index 0000000..71e70ee
--- /dev/null
+++ b/ap/libc/glibc/glibc-2.23/string/argz-insert.c
@@ -0,0 +1,63 @@
+/* Routines for dealing with '\0' separated arg vectors.
+   Copyright (C) 1995-2016 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Written by Miles Bader <miles@gnu.ai.mit.edu>
+
+   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 <argz.h>
+#include <string.h>
+#include <stdlib.h>
+
+/* Insert ENTRY into ARGZ & ARGZ_LEN before BEFORE, which should be an
+   existing entry in ARGZ; if BEFORE is NULL, ENTRY is appended to the end.
+   Since ARGZ's first entry is the same as ARGZ, argz_insert (ARGZ, ARGZ_LEN,
+   ARGZ, ENTRY) will insert ENTRY at the beginning of ARGZ.  If BEFORE is not
+   in ARGZ, EINVAL is returned, else if memory can't be allocated for the new
+   ARGZ, ENOMEM is returned, else 0.  */
+error_t
+__argz_insert (char **argz, size_t *argz_len, char *before, const char *entry)
+{
+  if (! before)
+    return __argz_add (argz, argz_len, entry);
+
+  if (before < *argz || before >= *argz + *argz_len)
+    return EINVAL;
+
+  if (before > *argz)
+    /* Make sure before is actually the beginning of an entry.  */
+    while (before[-1])
+      before--;
+
+  {
+    size_t after_before = *argz_len - (before - *argz);
+    size_t entry_len = strlen  (entry) + 1;
+    size_t new_argz_len = *argz_len + entry_len;
+    char *new_argz = realloc (*argz, new_argz_len);
+
+    if (new_argz)
+      {
+	before = new_argz + (before - *argz);
+	memmove (before + entry_len, before, after_before);
+	memmove (before, entry, entry_len);
+	*argz = new_argz;
+	*argz_len = new_argz_len;
+	return 0;
+      }
+    else
+      return ENOMEM;
+  }
+}
+weak_alias (__argz_insert, argz_insert)