new file mode 100644
--- /dev/null
+++ b/lib/c-strstr.h
@@ -0,0 +1,45 @@
+/* Searching in a string.
+   Copyright (C) 2001-2003, 2006 Free Software Foundation, Inc.
+
+   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 2, 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, write to the Free Software Foundation,
+   Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
+
+
+/* The functions defined in this file assume a nearly ASCII compatible
+   character set.  */
+
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* Find the first occurrence of NEEDLE in HAYSTACK.
+   This function is safe to be called, even in a multibyte locale, if NEEDLE
+     1. consists solely of printable ASCII characters excluding '\\' and '~'
+        [this restriction is needed because of Shift_JIS and JOHAB]
+        or of the control ASCII characters '\a' '\b' '\f' '\n' '\r' '\t' '\v'
+        [this restriction is needed because of VISCII], and
+     2. has at least length 2
+        [this restriction is needed because of BIG5, BIG5-HKSCS, GBK, GB18030,
+         Shift_JIS, JOHAB], and
+     3. does not consist entirely of decimal digits, or has at least length 4
+        [this restricion is needed because of GB18030].
+   This function is also safe to be called, even in a multibyte locale, if
+   HAYSTACK and NEEDLE are known to both consist solely of printable ASCII
+   characters excluding '\\' and '~'.  */
+extern char *c_strstr (const char *haystack, const char *needle);
+
+#ifdef __cplusplus
+}
+#endif