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)

mdoc: move CAVEATS, BUGS and SECURITY CONSIDERATIONS sections to the
bottom of the manpages and order them consistently.

GNU groff doesn't care about the ordering, and doesn't even mention
CAVEATS and SECURITY CONSIDERATIONS as common sections and where to put
them.

Found by: mdocml lint run
Reviewed by: ru

mdoc: order prologue macros consistently by Dd/Dt/Os

Although groff_mdoc(7) gives another impression, this is the ordering
most widely used and also required by mdocml/mandoc.

Reviewed by: ru
Approved by: philip, ed (mentors)

The NetBSD Foundation has granted permission to remove clause 3 and 4 from
their software.

Obtained from: NetBSD

Teach fmtcheck() about wint_t, intmax_t, char *, intmax_t *, and
wide string arguments.

Also simplify the code that handles length modifiers and make it
more conservative. For instance, be explicit about the modifiers
allowed for %d, rather than assuming that anything other than L,
q, t, or z implies an int argument.

Mechanically kill hard sentence breaks.

mdoc(7) police: "The .Fa argument.".

Add a Bugs section and note that fmtcheck() is out of sync with printf();
it does not recognise any of the conversions or modifiers added in C99.

can not -> cannot.

Move appropriate information out of `DESCRIPTION' and into `SECURITY
CONSIDERATIONS'.

Sponsored by: DARPA, NAI Labs

mdoc(7) police: Use the new .In macro for #include statements.

mdoc(7) police: expand plain text xrefs.

mdoc(7) police: fix markup.

Add fmtcheck(), a function for checking consistency of format string
arguments where the format string is obtained from user data, or
otherwise difficult to verify statically.

Example usage:

printf(fmtcheck(user_format, standard_format), arg1, arg2);

checks the format string user_format for consistency (same number/order/
type of format operators) with standard_format. If they differ,
standard_format is used instead to avoid potential crashes or security
violations.

Obtained from: NetBSD
Reviewed by: -arch