adjust_exif_parameters only needed in JPEG_LIB_VER > 70

The invocation of this function is wrapped in an ifdef JPEGLIB >70
but the definition of the function wasn't.  This change adds the
ifdef around the function definition.

transupp.c

@@ -1171,6 +1171,7 @@ transpose_critical_parameters (j_compress_ptr dstinfo)
 }
 
 
+#if JPEG_LIB_VERSION >= 70
 /* Adjust Exif image parameters.
  *
  * We try to adjust the Tags ExifImageWidth and ExifImageHeight if possible.
@@ -1325,6 +1326,7 @@ adjust_exif_parameters (JOCTET FAR * data, unsigned int length,
     offset += 12;
   } while (--number_of_tags);
 }
+#endif
 
 
 /* Adjust output image parameters as needed.