libc syslog, syslogd, logger, uds fixes

changes necessary for libc syslog() using a unix domain socket.

	. libc syslog: don't use send() connect() for unix
	  datagram sockets, minix wants write() and ioctl()
	. syslogd: listen on _PATH_LOG unix domain socket
	. logger: warnings fixes
	. pfs: make uds dgram socket type nonblocking so
	  syslog() doesn't block
	. vfs: add sanity check for empty fd in unpause()

Change-Id: Ied136c6fe0cc288f5a53478f1eebccc1ab1f39fb
tty: i386: rs232 fix

	. ignore interrupt (stop interrupt check loop) if
	  interrupt bit not set; limit loop too
	. mask off other bits when testing bits in the status register
	. this fixes rs232 output that would otherwise never get re-triggered
	  as too many bits were set in the status byte to match the
	  possibilities.

Change-Id: I311c93377fa8fb477ee9a756455fdeda780e6ba1
init: handle getty string of "" (default)

	. the default entry for disabled ttys for getty
	  in /etc/ttys is "", but init crashed on handling that
	  string.

Change-Id: Ib7cd6c6869e338f47df0aa5abed36f15eda4f6ff
inline sendnb should not call send vector

	. also vfs has to reply to a vm call - so use asynsend for that

Change-Id: I30ac1e591191dea5c99e25b03151a4415d1151b0
is: leave newline for stacktrace for SF9 dump

	. otherwise the standard console screen can't hold them

Change-Id: Iea2c047b715bc456747aace8957d8c5eeb94d0fa
allow ldd mmap fallback

Change-Id: Ia7b8aa88c3f063c804869065719ac0cbf049b7dd
arm:no longer rely on a 1:1 phys mapping for device memory.

Change-Id: Ie3f61069f882c37dbb81dee813fdfd883e7468cf
arm:remove pre 1:1 mapping workarounds.

Change-Id: I5a690cf5a561cdca9b9c1f031402f80fd203c92d
vfs: patch for unpause()/revive() race condition

	. unpause() and revive() can race - revive() can run during
	  a device i/o unblock, causing two sendnb()s to occur, and the
	  2nd one to fail
	. this can easily happen when a process is blocking on tty and
	  is then killed by a signal - tty cancels the i/o and then
	  kills the process by a signal

Change-Id: Ia319acaedfa336b78c030a2c4af7246959bdcf87
some arm uart fixes

	. always keep reading data from uart so the interrupt is
	  not continually asserted if data is sent but no process
	  reads it
	. increase tx & rx fifo trigger levels -> reduces the number
	  of interrupts necessary
	. bigger rx/tx buffers

Change-Id: I3cf7c73b22ae2fc091b845d516ba4aa53e892cda
a few DBG=-g build fixes, both arches

	- setlogin() not available
	- softfloat needed in -lminc for arm
	- libminc: we have to set LIBCDIR for the included files,
	  so use that instead of LIBCSRCDIR

Change-Id: I7f92621ebbca9ce08dc377b3fa61dee089071757