According to style(9):
> normally, include <sys/types.h> OR <sys/param.h>, but not both.
(<sys/param.h> already includes <sys/types.h> when LOCORE is not defined).

Eliminates -Wmissing-prototypes warnings with gcc

As of FreeBSD 6, devices can only be opened through devfs. These device
nodes don't have major and minor numbers anymore. The st_rdev field in
struct stat is simply based a copy of st_ino.

Simply display device numbers as hexadecimal, using "%#jx". This is
allowed by POSIX, since it explicitly states things like the following
(example taken from ls(1)):

	"If the file is a character special or block special file, the
	size of the file may be replaced with implementation-defined
	information associated with the device in question."

This makes the output of these commands more compact. For example, ls(1)
now uses approximately four columns less. While there, simplify the
column length calculation from ls(1) by calling snprintf() with a NULL
buffer.

Don't be afraid; if needed one can still obtain individual major/minor
numbers using stat(1).

- Make sure the mode argument is either a character or a block device.
- Use S_IS*() instead of checking S_IF*-flags by hand.
- Don't use kern.devname when the argument is already NODEV.
- Always call snprintf with the proper amount of arguments corresponding
  with the format.
- Perform some whitespace fixes. Tabs instead of 4 spaces, missing space
  for return statement.
- Remove unneeded includes.

clause.

# If I've done so improperly on a file, please let me know.

the function definition.

Format other unknown devices consistently in hex.

to a size_t (not to an int).

MFC after:	2 days