Add strptime into the source pool for those systems that don't have it.

Originally committed as revision 818 to svn://svn.ffmpeg.org/ffmpeg/trunk

libav/strptime.h

+/* strptime.h
+ *
+ * $Id$
+ *
+ * Ethereal - Network traffic analyzer
+ * By Gerald Combs <gerald@ethereal.com>
+ * Copyright 1998 Gerald Combs
+ *
+ * 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
+ * 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, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
+ */
+
+#ifndef __STRPTIME_H__
+#define __STRPTIME_H__
+
+/*
+ * Version of "strptime()", for the benefit of OSes that don't have it.
+ */
+extern char *strptime(const char *, const char *, struct tm *);
+
+#endif