[CFT][PATCH] symlinks - against -pre3

[Alexander Viro]

        Well, since some part of the previous patch went into -pre2...
Variant rediffed against -pre3 is on ftp.math.psu.edu/pub/viro/as-patch-23
News:
        added missing SetPageUptodate to NCPFS part (thanks, Petr ;-) and
into AFFS/EFS parts. The rest was OK.

Please, help testing it. Currently it differs from the main tree in AFFS,
EFS, HPFS, ISOFS, NCPFS and UMSDOS. And in the fact that it raises the
limit on nested symlinks to 32.