MFC	r268926, r268930, r268983:

Use a correct errno in freopen.
Use EBADF instead of EINVAL when working around incorrect O_ACCMODE.

Adjust errno on failed prepwrite.

rewind: always clear error indicator as required by POSIX.

Obtained from:	Apple Inc. (Libc 997.90.3)
Phabric:	D442
MFC	r269124:
strftime() xlocale cleanups.

Replace fprintf_l with fputs when output is unformatted.
Use locale_t in _conv() since it was using sprintf (now sprintf_l)
Use locale_t on _yconv() since it calls _conv()

Obtained from:	Apple Inc. (Libc 997.90.3)
CR:		D482
Reviewed by:	theraven
MFC	r268066:
regex(3): Add support for \< and \> word delimiters

Solaris and other OSs have support for \< and \> as word
delimiters in utilities like sed(1). These are useful to
have for general compatiblity with Solaris but should be
avoided for portability with other systems, including the
traditional BSDs.

Bump __FreeBSD_version as this is likely to affect some
userland utilities.

Reference:
https://www.illumos.org/issues/516

PR:		bin/153257
Obtained from:	Illumos