new file mode 100644
--- /dev/null
+++ b/lib/wcsncmp-impl.h
@@ -0,0 +1,36 @@
+/* Compare two wide strings.
+   Copyright (C) 1999, 2011 Free Software Foundation, Inc.
+   Written by Bruno Haible <bruno@clisp.org>, 1999.
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program 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 General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+int
+wcsncmp (const wchar_t *s1, const wchar_t *s2, size_t n)
+{
+  for (; n > 0;)
+    {
+      wchar_t wc1 = *s1++;
+      wchar_t wc2 = *s2++;
+      if (wc1 != (wchar_t)'\0' && wc1 == wc2)
+        {
+          n--;
+          continue;
+        }
+      /* Note that wc1 and wc2 each have at most 31 bits.  */
+      return (int)wc1 - (int)wc2;
+             /* > 0 if wc1 > wc2, < 0 if wc1 < wc2,
+                = 0 if wc1 and wc2 are both '\0'.  */
+    }
+  return 0;
+}