More cleanup and sorting on header section

OK tb@ and he also pointed out that for consistency with rest of the tree we
should include termios.h instead of sys/ttydefaults.h, where applicable

Set as __dead a few more functions, that don't return, on games/

With precious tip, help and also OK from tb@

Declare usage() functions as __dead void, if they don't return, on games section.

Found another one in arithmetic(6) which also didn't return, and removed a function from number(6) which is not used anymore.

OK tb@

Drop pledge("getpw") and pwd.h and use the now usual
LOGNAME -> USER -> getlogin() -> ??? fallback
in the score file, as requested by tedu@

Man page bits adapted from jmc@'s tweaks to snake.6

Move scorefile to $HOME. The nice implementation of the score file
depends on getpwuid(), so add "getpw" to the rest of the required
pledges: "stdio rpath wpath cpath tty".

Improve robots(6) by using timespec*() functions, replacing gettimeofday()
with clock_gettime(MONOTONIC) to avoid clock changes and replacing poll()
with ppoll() to deal better with timespec.

ok guenther@.

Eliminate pointless use of <sys/param.h>, <sys/file.h>, <sys/sockio.h>,
and <sys/ttydefaults.h>
Replace MAXPATHLEN with PATH_MAX and MAXLOGNAME with LOGIN_NAME_MAX
Pull in <limits.h> where needed
Prefer sizeof(var) over MAXFOO or FOO_MAX

ok deraadt@

select() to poll() conversions
ok tedu (... other games maintainer absent)

Remove the advertising clause in the UCB license which Berkeley
rescinded 22 July 1999. Proofed by myself and Theo.

Part one of userland __P removal. Done with a simple regexp with some minor hand editing to make comments line up correctly. Another pass is forthcoming that handles the cases that could not be done automatically.

Enable realtime mode, use native curses functions when available, tidy man
page, and use MAXLOGNAME for scorefile (this makes new scorefiles incompatible
with old ones). Realtime idea and some code from d@.

More largely NetBSD-inspired code cleanup

Scorefile bugfix and minor code cleaning, some from NetBSD

branches: 1.1.1;
Initial revision