Sync with gnulib 62bb7a8bf95807d6339e1e17fc0d21c319b280a2.

* src/filemanager/lib/mountlist.c: port to HP NonStop.
(hasmntopt) [!HAVE_HASMNTOPT]: New function.
(MNT_IGNORE) [MNTOPT_IGNORE]: Use it.

Signed-off-by: Andrew Borodin <aborodin@vmail.ru>