(we_are_root): Now global.

(we_are_root): Now global.
(struct delayed_symlink): New type.
(delayed_symlink_head): New var.
(extr_init, fatal_exit):
Invoke extract_finish on fatal errors, not apply_delayed_set_stat.
(set_mode, set_stat): Pointer args are now const pointers.
(check_time): New function.
(set_stat): Warn if setting a file's timestamp to be the future.
(make_directories): Do not save and restore errno.
(maybe_recoverable): Set errno to ENOENT if we cannot make missing
intermediate directories.
(extract_archive):
Invoke apply_nonancestor_delayed_set_stat here, not in caller.
Extract potentially dangerous symbolic links more carefully, deferring their
creation until the end, and using a regular file placeholder in the meantime.
Do not remove trailing / and /. from file names.
Do not bother checking for ".." when checking whether a directory
loops back on itself, as loopbacks can occur with symlinks too.
Also, in that case, do not bother saving and restoring errno; just
set it to EEXIST.
(apply_nonancestor_delayed_set_stat): A prefix is a potential ancestor if
it ends in slash too (as well as ending in a char just before slash).
(apply_delayed_set_stat): Remove.
(apply_delayed_symlinks, extract_finish): New functions.