Copy stable/9 to releng/9.3 as part of the 9.3-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Copy head to stable/9 as part of 9.0-RELEASE release cycle.

Approved by: re (implicit)

Restore the previous state after a FILL operation in properties_read()
rather than forcing the state to LOOK. If we are in the middle of parsing
a line when we have to do a FILL we would have lost any token we were in
the middle of parsing and would have treated the next character as being
at the start of a new line instead.

PR: kern/89181
Submitted by: Antony Mawer gnats at mawer dot org
MFC after: 1 week

Tidy up. Sort headers.

Now return NULLified struct in case of empty config file
(previous variant return NULL pointer for both empty file case and error case,
so caller can't sense error properly).

It not affect existen programs because property_find() now returns NULL
for both NULL pointer and NULLified struct.

Handle read errors

Add (unsigned char) cast to ctype macros
Handle NULL return from malloc and strdup

Replace various spelling with FALLTHROUGH which is lint()able

Add __FBSDID()s to libutil

Eliminate inconsistency where a value that contains only whitespace
confuses the parser.

Approved by: jkh

Added PROPERTY_MAX_VALUE and PROPERTY_MAX_NAME defines to libutil.h so
that applications know how large of a buffer they must allocate before
calling property_find(). Also added a $FreeBSD$ tag while I'm here.

Approved by: jkh

Better document the file format, add in support for nested {}'s in multi-line
property values.

Now take stdio.h out of files that don't require it.

o move path in libutil.h to paths.h
o make property_read() take a fd instead to avoid stdio.h mess
o update auth to new interface.

Correct a build error that got past my build test somehow.

Add a simple mechanism for reading property lists from files (which
I'll convert sysinstall to use shortly) and a simple call which uses
this mechanism to implement an /etc/auth.conf file. I'll let Mark Murray
handle the format and checkin of the sample auth.conf file.
Reviewed by: markm