getdirentries(2) reports records of deleted files with d_fileno set to zero
and readdir(3) must not return them. On FFS such a record survives an unlink
whenever it is the first one in a directory block, so any directory larger
than a single 512-byte block reported ghost entries for files that were
already gone.

That made Tcl's glob (via libtcl8.6) see deleted files, causing the
modernc.org/libsqlite3 openbsd/amd64 test failures delete_db-1.3.1,
delete_db-1.4.1, multiplex-2.4.5, multiplex-5.3.prep and quota-5.3.prep.
The failures only showed up in full-suite runs, once the shared working
directory had grown past one block.

Also stop iterating on a malformed d_reclen rather than spinning on it,
matching the checks in OpenBSD's _readdir_unlocked().

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>