Merge a lot of duplicated special file handling into fs/devices.c, and
make drivers register their major numbers properly.

VFS layer gets fsync virtual function.

Compressed image boot, with the kernel loaded into high memory..

[original announcement below]

I'm starting soon to run out of patchlevel numbers for 0.99, but I made
a new release anyway (and long-time linux hackers remember my less than
completely logical numbering: when I run out of numbers I'll start using
alphabetical characters and other fun characters to indicate new
versions :-)

0.99pl6 is mainly a syncronization release: it fixes a few bugs and
changes the behaviour of 'vhangup()' to be more standard.  The vhangup()
changes will break some init/login stuff that depended on the earlier
incorrect behaviour - not everybody may want to use pl6 until you are
sure your init/login will work happily with it.  Better do these things
before 1.0 than to break it later.

Patchlevel 6 also changes the vfs functions for special devices as well
as adding a 'fsync' field to the inode-operations structure.  Thus
ext2fs and xfs need updating.  Remy and Xia? The special file and fifo
handling code is no longer supposed to be in the fs-dependent layer, but
is handled by the vfs routines, as it's the same for all "normal"
filesystems.

Ok, here are the actual changes/features of pl6:
- the kernel can be loaded in gzipped format and de-compressed at
  startup beyond the 1MB mark.  Good for bootable rootdisks.  Patches
  mainly by Hannu Savolainen.
- I finally enabled NMI's everywhere (except at the bootup sequence),
  so if you have memory errors, they will hopefully now result in
  kernel messages ("NMI received..")
- the device registration code for special devices.  Special files are
  now registered with a special "register_[chr|blk]dev()" function.
- consolidated fifo/special dev handling
- vhangup patches.  Note that these may break init/login badly, at
  least if you are using poeigl-1.7.  Be careful that you don't get
  totally locked out of your machine.
- the procfs NULL-dereferencing bugfix (michaelkjohnson)
- literal next character handling (very losely based on a patch I
  received: I essentially rewrote it with final fixes by jrs).
- fpu-emu bugfixes by Bill Metzenthen - fixes the "internal error 112"
  bug as well as a sign bug with zero.
- fdomain driver fixes
- various other minor fixes (wrongly replying to bad ip messages etc)

I'm still not sure about the 387 error detection code: I have had a
couple of messages that would suggest that some early clone 387's have
problems with math exceptions in protected mode.  With the new (as of
99pl5) test at startup this can lead to problems at boot-time.  Please
mail me directly if you seem to have problems with this (it should be
obvious in pl6 due to debugging messages at startup).

            Linus