sh: Remove prefix() function. Use strncmp() instead.
Older versions of flex (like the one used in FreeBSD <= 9) expect the
output file name to follow the -o flag immediately, with no intervening
whitespace.

Reported by:	ian@
MFC after:	1 week
Fix build without INVARIANTS defined by getting rid of unused variable 'exc'.

Reported by:	adrian, stefanf
Fix the build when DTrace isn't enabled.

Reported by:	stefanf
X-MFC-With:	r268600
Update fflush(3) to return success on a read-only stream.

This has small changes to what Apple uses for compliance
with SUSv3. The changes cause no secondary effects in the
gnulib tests (we pass them).

Obtained from:	Apple Inc. (Libc 997.90.3 with changes)
Reviewed by:	bde
Phabric:	D440
In "procstat -v" (VM), spell out 'FL' to 'FLAG' since there are two extra
columns available anyway.  Also left align as we tend to do for flags
fields, although you can't see that currently as the string fully fills
that available columns.

MFC after:	3 days
Sponsored by:	DARPA, AFRL
Use a correct errno in freopen.

Use EBADF instead of EINVAL when working around incorrect O_ACCMODE.

Phabric:	D442
Obtained from:	Apple Inc. (Libc 997.90.3)
Reviewed by:	jilles
MFC after:	1 week
sh: Allow arbitrarily large numbers in break and continue.

The argument is capped to loopnest, so strtol()'s [ERANGE] can be ignored.
Const-ify a character string.

Obtained from:	Apple Inc. (Libc 997.90.3)
MFC after:	3 days
Add new device ID.

MFC after:	1 week
PR:		191959
Adjust errno on failed prepwrite.

Obtained from:	Apple Inc. (Libc 997.90.3)
Phabric:	D442
MFC after:	1 week
Correct spelling errors in ctld.8.  While here, correct similar errors
in ctl.conf.5 and fix a couple of contractions.

PR:		191984
Submitted by:	olgeni
MFC after:	1 week
Add the PCBGROUPS manpage.

Thanks to wblock for helping me with this manpage.