- build only if either CONFIG_LEGACY_PTYS or CONFIG_UNIX98_PTYS are set
  instead of testing in the file

- try to keep big CONFIG_LEGACY_PTYS and CONFIG_UNIX98_PTYS ifdef blocks
  at the end of the file instead of cluttering all over
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>