Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

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

Add a set of manual pages for pthread[_attr]_[sg]etaffinity(3).

Reviewed by: davidxu
MFC after: 2 weeks

Hide the implementation details about multiple threading libraries
from the synopses of pthread*(3) manpages.

Reviewed by: deischen, davidxu

Remove mentions of libc_r.

Document interfaces that are supported by libthr.

Have a single set of POSIX threads man pages. The LIBRARY section
of each manpage lists libraries that have corresponding interfaces
implemented.

Prodded by: threads
Reviewed by: deischen

mdoc(7) police: Scheduled sweep.

Add cross reference for pthread_attr_get_np()

Add pthread_attr_getstack() and pthread_attr_setstack().

Submitted by: Craig Rodrigues <rodrigc@attbi.com>

The .Fn function

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

Spell "FreeBSD" with "F" and "BSD" in uppercase.

Implement pthread_attr_[gs]etguardsize(). Non-default-size stacks used to
be malloc()ed, but they are now allocated using mmap(), just as the
default-size stacks are. A separate cache of stacks is kept for
non-default-size stacks.

Collaboration with: deischen

Remove whitespace at EOL.

/^\.St/ s/-iso9945-1/-p1003.1-96/

Change my email address in the copyright notices for the sake of consistency
(jasone@canonware.com --> jasone@freebsd.org).

Fixed misspelling of a struct tag in a function parameter type.

mdoc(7) cleanup:

. use real function names as `.Nm' macro argument in NAME section. It allows
them to appear in apropos(1) or whatis(1) output.

. replace empty lines with `.Pp' macro.

. replace hardcoded standard names with their `.St' macro equivalents.

. sort cross references in SEE ALSO section

Add missing .El macro.

Add missing man pages. Fix various compliance bugs, mostly having to do with
error return values. Implement pthread_mutexattr_gettype().

PR: docs/16537, docs/17538