Remove $FreeBSD$: one-line sh pattern

Remove /^\s*#[#!]?\s*\$FreeBSD\$.*$\n/

Remove pc98 support completely.
I thank all developers and contributors for pc98.

Relnotes: yes

A new jail(8) with a configuration file, to replace the work currently done
by /etc/rc.d/jail.

Create the altix project branch. The altix project will add support
for the SGI Altix 350 to FreeBSD/ia64. The hardware used for porting
is a two-module system, consisting of a base compute module and a
CPU expansion module. SGI's NUMAFlex architecture can be an excellent
platform to test CPU affinity and NUMA-aware features in FreeBSD.

The last big commit: let usr.sbin/ use WARNS=6 by default.

- Import the HEAD csup code which is the basis for the cvsmode work.

Cleanup usr.sbin/fd* so they can compile under WARNS=6.

fdcontrol/fdcontrol.c:
- Add const constraint to an intermediate value
which is not supposed to be changed elsewhere.
fdread/fdread.c:
- Use _devname in favor of devname to avoid name
conflicit.
- -1 is less than any positive number so in order
to get the block to function, we should get the
block a little earlier.
- Cast to remove signed when we are sure that a
return value is positive, or is compared with
an positive number (tracknumber of a floppy
disk is not likely to have UINT_MAX/2 anyway)
fdread/fdutil.c:
- Use more specific initializer
fdwrite/fdwrite.c:
- Use static on format_track since it's not
referenced in other places.
- Use const char* to represent string constant.

Bump WARNS accordingly.

Add PC98 supports.

Submitted by: Watanabe Kazuhiro <CQG00620@nifty.ne.jp> (mostly)

Remove GCC'isms in CFLAGS.

Break out the function to print the FDC error information into
fdutil.c so it can be used elsewhere.

Initial import of fdread(1), a logical counterpart to fdwrite(1).

Its main purpose is to adapt automatically to the floppy parameters
(in particular the track size for efficient reading), and to allow a
simple error recovery for CRC-errored sectors. Requires the newly
added fdc(4) options.