Add libexif to deps/third_party.

libexif/sources/test/test-sorted.c

+/* test-sorted.c
+ *
+ * This test ensures that the ExifTagTable[] array is stored in sorted
+ * order. If that were not so, then it a binary search of the array would
+ * not give correct results.
+ *
+ * Copyright 2009 Dan Fandrich <dan@coneharvesters.com>
+ *
+ * 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
+ */
+
+#include <libexif/exif-tag.h>
+#include <stdio.h>
+
+int
+main (void)
+{
+        int rc = 0;
+        unsigned int i, num;
+        ExifTag last = 0, current;
+        num = exif_tag_table_count() - 1; /* last entry is a NULL terminator */
+        for (i=0; i < num; ++i) {
+                current = exif_tag_table_get_tag(i);
+                if (current < last) {
+                        printf("Tag 0x%04x in ExifTagTable[] is out of order\n",
+                                current);
+                        rc = 1;
+                }
+                if (exif_tag_table_get_name(i) == NULL) {
+                        printf("Tag 0x%04x has a NULL name\n", current);
+                        rc = 1;
+                }
+                last = current;
+        }
+
+        return rc;
+}