Add libexif to deps/third_party.

libexif/sources/libexif/olympus/mnote-olympus-entry.h

+/* mnote-olympus-entry.h
+ *
+ * Copyright (c) 2002 Lutz Mueller <lutz@users.sourceforge.net>
+ *
+ * This 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 of the License, or (at your option) any later version.
+ *
+ * This 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 this library; if not, write to the
+ * Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+ * Boston, MA  02110-1301  USA.
+ */
+
+#ifndef __MNOTE_OLYMPUS_ENTRY_H__
+#define __MNOTE_OLYMPUS_ENTRY_H__
+
+#include <libexif/exif-format.h>
+#include <libexif/exif-byte-order.h>
+#include <libexif/olympus/mnote-olympus-tag.h>
+
+typedef struct _MnoteOlympusEntry        MnoteOlympusEntry;
+
+struct _MnoteOlympusEntry {
+        MnoteOlympusTag tag;
+        ExifFormat format;
+        unsigned long components;
+
+        unsigned char *data;
+        unsigned int size;
+
+        ExifByteOrder order;
+};
+
+char *mnote_olympus_entry_get_value (MnoteOlympusEntry *entry, char *val, unsigned int maxlen);
+
+#endif /* __MNOTE_OLYMPUS_ENTRY_H__ */