Style(9) cleanup.

Style(9) cleanup.

- Convert K&R-style function definitions to ANSI style.
- Remove ``register'' keywords.
- (fdformat only) Remove/add whitespace around operators, add parens
  after sizeof and return, use NULL instead of O for null pointer,
  and remove (void) casts on ignored return values,
- Move local variable out of redundant inner block.
- Remove redundant return from end of void functions.
- *argv[] -> **argv.
- NOT REACHED -> NOTREACHED.
- Correct wording of #endif hint-comment to __DragonFly__.