sigaction(2),sigwait(2),sigwaitinfo(2): Remove [EFAULT] error condition.

Passing an invalid pointer results in undefined behaviour.

The wrappers in libthr access some of the data pointed to by the arguments
in userland, so that an invalid pointer will cause a signal and not an
[EFAULT] error return.

Furthermore, if the [EFAULT] error occurs when the kernel is writing, it is
not a proper error in the sense that the call still commits (changing the
signal disposition or accepting the signal).

MFC after:	1 week

lib/libc/sys/sigaction.2

@@ -28,7 +28,7 @@
 .\"	From: @(#)sigaction.2	8.2 (Berkeley) 4/3/94
 .\" $FreeBSD$
 .\"
-.Dd April 18, 2010
+.Dd September 27, 2012
 .Dt SIGACTION 2
 .Os
 .Sh NAME
@@ -586,13 +586,6 @@ system call
 will fail and no new signal handler will be installed if one
 of the following occurs:
 .Bl -tag -width Er
-.It Bq Er EFAULT
-Either
-.Fa act
-or
-.Fa oact
-points to memory that is not a valid part of the process
-address space.
 .It Bq Er EINVAL
 The
 .Fa sig

lib/libc/sys/sigwait.2

@@ -27,7 +27,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd August 24, 2011
+.Dd September 27, 2012
 .Dt SIGWAIT 2
 .Os
 .Sh NAME
@@ -107,9 +107,6 @@ The
 .Fa set
 argument
 specifies one or more invalid signal numbers.
-.It Bq Er EFAULT
-Any arguments point outside the allocated address space or there is a
-memory protection fault.
 .El
 .Sh SEE ALSO
 .Xr sigaction 2 ,

lib/libc/sys/sigwaitinfo.2

@@ -27,7 +27,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd August 24, 2011
+.Dd September 27, 2012
 .Dt SIGTIMEDWAIT 2
 .Os
 .Sh NAME
@@ -172,9 +172,6 @@ system calls fail if:
 .Bl -tag -width Er
 .It Bq Er EINTR
 The wait was interrupted by an unblocked, caught signal.
-.It Bq Er EFAULT
-Any arguments point outside the allocated address space or there is a
-memory protection fault.
 .Pp
 .El
 The