+void a_gpx_write_file_options ( GpxWritingOptions *options, VikTrwLayer *trw, FILE *f );
+void a_gpx_write_track_file ( const gchar *name, VikTrack *track, FILE *f );
+void a_gpx_write_track_file_options ( GpxWritingOptions *options, const gchar *name, VikTrack *t, FILE *f );