posix/wordexp-tst.sh

[Joseph S. Myers]

posix/wordexp-tst.sh leaves its output files behind in TMPDIR after
running, if TMPDIR is set.  If TMPDIR were set to a shared directory for
some reason (e.g. set to /var/tmp because of /tmp being full), the usual
symlink attacks also apply.

Suggested fix: always create the wordexp-test-result files in the build
directory; ignore TMPDIR.  "make clean" will remove them from there so
there's no need for the script to clean them up itself.

-- 
Joseph S. Myers
jsm28@cam.ac.uk