Fetch libexif 0.6.21 to include the security fixes.

libexif/sources/libexif/exif-tag.c

 /* exif-tag.c
  *
  * Copyright (c) 2001 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, 
@@ skipping 175 matching lines @@
         {EXIF_TAG_GPS_DEST_BEARING_REF, "GPSDestBearingRef", N_("Reference for Bearing of Destination"),
          N_("Indicates the reference used for giving the bearing to "
             "the destination point. 'T' denotes true direction and 'M' is "
             "magnetic direction."), ESL_GPS},
         {EXIF_TAG_GPS_DEST_BEARING, "GPSDestBearing", N_("Bearing of Destination"),
          N_("Indicates the bearing to the destination point. The range "
             "of values is from 0.00 to 359.99."), ESL_GPS},
         {EXIF_TAG_GPS_DEST_DISTANCE_REF, "GPSDestDistanceRef", N_("Reference for Distance to Destination"),
          N_("Indicates the unit used to express the distance to the "
             "destination point. 'K', 'M' and 'N' represent kilometers, miles "
-            "and knots."), ESL_GPS},
+            "and nautical miles."), ESL_GPS},
         {EXIF_TAG_GPS_DEST_DISTANCE, "GPSDestDistance", N_("Distance to Destination"),
          N_("Indicates the distance to the destination point."), ESL_GPS},
         {EXIF_TAG_GPS_PROCESSING_METHOD, "GPSProcessingMethod", N_("Name of GPS Processing Method"),
          N_("A character string recording the name of the method used "
             "for location finding. The first byte indicates the character "
             "code used, and this is followed by the name "
             "of the method. Since the Type is not ASCII, NULL termination is "
             "not necessary."), ESL_GPS},
         {EXIF_TAG_GPS_AREA_INFORMATION, "GPSAreaInformation", N_("Name of GPS Area"),
          N_("A character string recording the name of the GPS area. The "
@@ skipping 968 matching lines @@
 exif_tag_get_support_level_in_ifd (ExifTag tag, ExifIfd ifd, ExifDataType t)
 {
         if (ifd >= EXIF_IFD_COUNT)
                 return EXIF_SUPPORT_LEVEL_UNKNOWN;
 
         if (t >= EXIF_DATA_TYPE_COUNT)
                 return get_support_level_any_type (tag, ifd);
 
         return get_support_level_in_ifd (tag, ifd, t);
 }