on EPIPE for all file descriptor types:
- provide O_NOSIGPIPE for open,kqueue1,pipe2,dup3,fcntl(F_{G,S}ETFL) [NetBSD]
- provide SOCK_NOSIGPIPE for socket,socketpair [NetBSD]
- provide SO_NOSIGPIPE for {g,s}seckopt [NetBSD/FreeBSD/MacOSX]
- provide F_{G,S}ETNOSIGPIPE for fcntl [MacOSX]
set close-on-exec on creation (http://udrepper.livejournal.com/20407.html).
- Add F_DUPFD_CLOEXEC to fcntl(2).
- Add MSG_CMSG_CLOEXEC to recvmsg(2) for unix file descriptor passing.
- Add dup3(2) syscall with a flags argument for O_CLOEXEC, O_NONBLOCK.
- Add pipe2(2) syscall with a flags argument for O_CLOEXEC, O_NONBLOCK.
- Add flags SOCK_CLOEXEC, SOCK_NONBLOCK to the socket type parameter
for socket(2) and socketpair(2).
- Add new paccept(2) syscall that takes an additional sigset_t to alter
the sigmask temporarily and a flags argument to set SOCK_CLOEXEC,
SOCK_NONBLOCK.
- Add new mode character 'e' to fopen(3) and popen(3) to open pipes
and file descriptors for close on exec.
- Add new kqueue1(2) syscall with a new flags argument to open the
kqueue file descriptor with O_CLOEXEC, O_NONBLOCK.
* Fix the system calls that take socklen_t arguments to actually do so.
* Don't include userland header files (signal.h) from system header files
(rump_syscallargs.h).
* Bump libc version for the new syscalls.
Use .Fn rather than .Nm macro in HISTORY and STANDARDS sections.
Use .At and .St macros instead of spelling out "Version 6 UNIX",
"IEEE 1003.1-1988 (POSIX)", etc.
