fts: fts_open: do not let an empty string cause immediate failure This is required in support of GNU rm, for which the command "rm A '' B" must process and remove both A and B, in spite of the empty string argument. * lib/fts.c (fts_open): Do not let the presence of an empty string cause fts_open to fail immediately. Most fts-using tools must be able to process all arguments, in order, and can be expected to diagnose such arguments themselves. Also, move declaration of local, "len", "down" to initialization.