Copy stable/10@r272459 to releng/10.1 as part of
the 10.1-RELEASE process.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

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

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.

This commit was generated by cvs2svn to compensate for changes in r76589,
which included commits to RCS files with non-trunk default branches.

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.