This would allow interested parties to do experimental runs with an
environment set appropriately to raise all the warnings throughout the
build; e.g. env WARNS=6 NO_WERROR=yes buildworld.
Not currently touching the numerous instances in ^/tools.
MFC after: 1 week
This also fixes a minor issue that was missed in the initial review; the
layout of the MFD_HUGE_* flags is actually not 1:1 bit:flag -- it instead
borrowed the Linux convention of how this is laid out since it was
originally implemented on Linux, the top 6 bits represent the shift required
for the requested page size.
This allows us to remove the flag <-> pgsize mapping table and simplify the
logic just prior to validation of the requested page size.
While we're here, fix two small nits:
- HUGETLB memfd shouldn't exhibit the SHM_GROW_ON_WRITE behavior. We can
only grow largepage shm by appropriately aligned (i.e. requested pagesize)
sizes, so it can't work in the typical/sane fashion. Furthermore, Linux
does the same, so let's be compatible.
- We don't allow MFD_HUGETLB without specifying a pagesize, so no need to
check for that later.
Reviewed by: kib (slightly earlier version)
Literally returning EINVAL from a function designed to return an fd makes
for interesting scenarios.
I cannot assign enough pointy hats to cover this one.
r365524 did accidentally invert this check that sets SHM_LARGEPAGE, leading
non-hugetlb memfd as unconfigured largepage shm and thus test failures when
we try to ftruncate or write to them.
PR: 249236
Discussed with: kib
Found this while trying to get macOS bootstrap to work again after OpenZFS merge.
Reviewed By: #zfs, freqlabs
Differential Revision: https://reviews.freebsd.org/D26192
largepage shm objects.
And since we can, add memfd_create(MFD_HUGETLB) support, hopefully
close enough to the Linux feature.
Reviewed by: markj
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D24652
for clang, as it uses clang specific builtins, and does not compile
correctly with gcc. Note that gcc packages usually come with their own
libatomic, providing these primitives.
PR: 230888
MFC after: 3 days
X-MFC-With: r364753
getlogin_r is specified by POSIX to to take a size_t len, not int. Fix our
version to do the same, bump the symbol version due to ABI change and
provide compat.
This was reported to break compilation of Ruby 2.8.
Some discussion about the necessity of the ABI compat did take place in the
review. While many 64-bit platforms would likely be passing it in a 64-bit
register and zero-extended and thus, not notice ABI breakage, some do
sign-extend (e.g. mips).
PR: 247102
Submitted by: Bertram Scharpf <software@bertram-scharpf.de> (original)
Submitted by: cem (ABI compat)
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D26335
This is being addressed as part of a side-patch I'm working on that builds
all the things with WARNS=6, instead of relying on it being supplied in just
shallow parts of the build with higher-level Makefile.inc.
Provide a prototype for mod_main and annotate the thread function argument
as unused.
MFC after: 1 week
In a side-change that I'm working on to start defaulting src builds to
WARNS=6 where WARNS isn't otherwise specified, GCC6 (and clang, to a lesser
extent) pointed out a number of issues with the resolv tests:
- Global method variable that gets shadowed in run_tests()
- Signed/unsigned comparison between i in run_tests() and hosts->sl_cur
The shadowed variable looks like it might actually be bogus as written, as
we pass it to RUN_TESTS -> run_tests, but other parts use the global method
instead. This change is mainly geared towards correcting that by removing
the global and plumbing the method through from run_tests -> run into the
new thread.
For the signed/unsigned comparison, there's no compelling reason to not just
switch i/nthreads/nhosts to size_t.
The review also included a change to the load() function that was better
addressed by jhb in r365302.
Reviewed by: ngie, pstef
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D24844
Implement the remaining pieces needed to allow userland timestamp reading.
Rewritten based on an intial essay into the problem by Justin Hibbits.
(Copyright changed to my own on his request.)
Tested on ppc64 (POWER9 Talos II), powerpcspe (e500v2 RB800), and
powerpc (g4 PowerBook).
Reviewed by: jhibbits (in irc)
Sponsored by: Tag1 Consulting, Inc.
Differential Revision: https://reviews.freebsd.org/D26347
MK_MALLOC_PRODUCTION option on -CURRENT.
Also, for the sake of backwards compatibility, support the old way of
enabling 'production malloc', e.g. by adding a define in make.conf(5).
MFC after: 1 week
X-MFC-With: r365371
For historical reasons, defining MALLOC_PRODUCTION in /etc/make.conf has
been used to turn off potentially expensive debug checks and statistics
gathering in the implementation of malloc(3).
It seems more consistent to turn this into a regular src.conf(5) option,
e.g. WITH_MALLOC_PRODUCTION / WITHOUT_MALLOC_PRODUCTION. This can then
be toggled similar to any other source build option, and turned on or
off by default for e.g. stable branches.
Reviewed by: imp, #manpages
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D26337
- Use getline() instead of fgetln(). This ensures the returned string
is always null-terminated without losing the last character if the
last line in a file doesn't have a newline. Also, while fgetln says
the returned buffer can be modified, that doesn't actually seem safe
as the current implementation means you are modifying stdio's
internal buffer.
- Remove a spurious if before an ATF_REQUIRE that was clearly supposed
to be non-optional.
- Remove a pointless compare of 'ptr' against '\0' (really NULL) that
duplicated the middle condition in the for().
- Once a comment is found, skip the rest of the line, not just the
current word.
Reviewed by: kevans
Obtained from: CheriBSD
Sponsored by: DARPA
Differential Revision: https://reviews.freebsd.org/D26278
variable name instead of LIBUCL (which would otherwise end up with the
staging directory used instead of the wanted source directory.)
Reviewed by: sjg
Obtained from: Juniper Networks, Inc.
ld.bfd in particular requires -lm to come after libifconfig on the
command line when linking rescue.
Reviewed by: freqlabs, adrian
Differential Revision: https://reviews.freebsd.org/D26258
CheriABI is pickier about the arguments to open(2) and crashes with a
fault if a mode isn't passed to an open() when O_CREATE is specified.
Reported by: CHERI
Reviewed by: brooks
Obtained from: CheriBSD
MFC after: 2 weeks
Sponsored by: DARPA
Differential Revision: https://reviews.freebsd.org/D26281
The size of the object at 'addr' is unknown and might be smaller than
the size of a pointer (e.g. some x86 instructions are smaller than a
pointer). Instead, just check that the address is in the bounds of
the program header.
Reported by: CHERI (indirectly)
Reviewed by: kib, brooks
Obtained from: CheriBSD
MFC after: 1 week
Sponsored by: DARPA
Differential Revision: https://reviews.freebsd.org/D26279
Previously this was counting the amount of spare room at the start of
the buffer that the string needed to move forward and passing that as
the number of bytes to copy to memmove rather than the length of the
string to be copied.
In the strfmon test in the test suite this caused the memmove to
overflow the allocated buffer by one byte which CHERI caught.
Reported by: CHERI
Reviewed by: kevans
Obtained from: CheriBSD
MFC after: 1 week
Sponsored by: DARPA
Differential Revision: https://reviews.freebsd.org/D26280
Currently we use a single bit to indicate whether the virtual page is
part of a superpage. To support a forthcoming implementation of
non-transparent 1GB superpages, it is useful to provide more detailed
information about large page sizes.
The change converts MINCORE_SUPER into a mask for MINCORE_PSIND(psind)
values, indicating a mapping of size psind, where psind is an index into
the pagesizes array returned by getpagesizes(3), which in turn comes
from the hw.pagesizes sysctl. MINCORE_PSIND(1) is equal to the old
value of MINCORE_SUPER.
For now, two bits are used to record the page size, permitting values
of MAXPAGESIZES up to 4.
Reviewed by: alc, kib
Sponsored by: Juniper Networks, Inc.
Sponsored by: Klara, Inc.
Differential Revision: https://reviews.freebsd.org/D26238
Use explicit typedefs for block thunk structures as in r264143.
Reviewed by: kib, adrian
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D26256
This changeset introduces the new libnetmap library for writing
netmap applications.
Before libnetmap, applications could either use the kernel API
directly (e.g. NIOCREGIF/NIOCCTRL) or the simple header-only-library
netmap_user.h (e.g. nm_open(), nm_close(), nm_mmap() etc.)
The new library offers more functionalities than netmap_user.h:
- Support for complex netmap options, such as external memory
allocators or per-buffer offsets. This opens the way to future
extensions.
- More flexibility in the netmap port bind options, such as
non-numeric names for pipes, or the ability to specify the netmap
allocator that must be used for a given port.
- Automatic tracking of the netmap memory regions in use across the
open ports.
At the moment there is no man page, but the libnetmap.h header file
has in-depth documentation.
Reviewed by: hrs
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D26171
Coverity flagged the scaling by sizeof(uzd). That is the type
of the pointer, so the scaling was already done by pointer arithmetic.
However, this was also passing a stack frame pointer to kvm_read,
so it was doubly wrong.
Move ZDOM_GET into the !_KERNEL section and use it in libmemstat.
Reported by: Coverity
Reviewed by: markj
MFC after: 2 weeks
Sponsored by: Dell EMC Isilon
Differential Revision: https://reviews.freebsd.org/D26213
In parallel builds, this should allow sqlite to start building earlier and
increase parallelism when building lib/. Looking at htop output during
buildworld/tinderbox, there are long phases where only one CPU is active
optimizing the massive sqlite3.c file since the build of libsqlite3 is
started quite late.
Reviewed By: emaste
Differential Revision: https://reviews.freebsd.org/D26169
performs are protected by an exclusive lock, even for statically linked
programs, it is safe to re-enable libunwind's FrameHeaderCache, which I
temporarily disabled in r364263.
Meanwhile upstream has also used the _LIBUNWIND_USE_FRAME_HEADER_CACHE
for this purpose, so the only thing needed is to add this as a
compile-time command line flag.
While here, reformat the CFLAGS lines a little bit.
MFC after: 6 weeks
X-MFC-With: r364284, r364423
warnings anymore for compiler-rt's atomic.c. This occurred because the
IS_LOCK_FREE_8 macro was not correctly defined to 0 for mips, and this
caused the compiler to emit a runtime call to __atomic_is_lock_free(),
and that triggers the warning.
MFC after: 2 weeks
X-MFC-With: r364753
sys/ccompile.h no longer uses #pragma ident, so we no longer need to worry
about unknown pragmas.
I fixed one WARNS issue in r363409 by annotating be_is_auto_snapshot_name's
lbh parameter __unused, then upstreamed the following changes to OpenZFS
that rode in with the merge:
- zfs_path_to_zhandle now takes a const char *path rather than a char *path,
since it won't be mutating the string it receives and I had no reason to
believe it will need to in the future. [OpenZFS PR #10605]
- Annotated some unused parameters on definitions inlined into headers as
such. [OpenZFS PR #10606]
We need to define the LUA_FLOAT_INT64 macro even if we don't use it (copied
from stand/luaconf.h). While touching luaconf.h.dist also sync it with the
the 5.3.5 release version (matches the one in lib/liblua).
Reviewed By: kevans
Differential Revision: https://reviews.freebsd.org/D25977
In most cases this simply builds the file from lib/libc for missing
functions (e.g. strlcpy on Linux etc.). In cases where this is not possible
I've added an implementation to tools/build/cross-build.
The fgetln.c/fgetwln.c/closefrom.c compatibility code was obtained from
https://gitlab.freedesktop.org/libbsd/libbsd, but I'm not sure it makes
sense to import it into to contrib just for these three bootstrap files.
Reviewed By: brooks
Differential Revision: https://reviews.freebsd.org/D25978
There have been several mentions on our mailing lists about missing
atomic functions in our system libraries (e.g. __atomic_load_8 and
friends), and recently I saw __bswapdi2 and __bswapsi2 mentioned too.
To address this, add implementations for the functions from compiler-rt
to the system compiler support libraries, e.g. libcompiler_rt.a and and
libgcc_s.so.
This also needs a small fixup in compiler-rt's atomic.c, to ensure that
32-bit mips can build correctly.
Bump __FreeBSD_version to make it easier for port maintainers to detect
when these functions were added.
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D26159
The primary benefit is maintaining a completely shared
code base with the community allowing FreeBSD to receive
new features sooner and with less effort.
I would advise against doing 'zpool upgrade'
or creating indispensable pools using new
features until this change has had a month+
to soak.
Work on merging FreeBSD support in to what was
at the time "ZFS on Linux" began in August 2018.
I first publicly proposed transitioning FreeBSD
to (new) OpenZFS on December 18th, 2018. FreeBSD
support in OpenZFS was finally completed in December
2019. A CFT for downstreaming OpenZFS support in
to FreeBSD was first issued on July 8th. All issues
that were reported have been addressed or, for
a couple of less critical matters there are
pull requests in progress with OpenZFS. iXsystems
has tested and dogfooded extensively internally.
The TrueNAS 12 release is based on OpenZFS with
some additional features that have not yet made
it upstream.
Improvements include:
project quotas, encrypted datasets,
allocation classes, vectorized raidz,
vectorized checksums, various command line
improvements, zstd compression.
Thanks to those who have helped along the way:
Ryan Moeller, Allan Jude, Zack Welch, and many
others.
Sponsored by: iXsystems, Inc.
Differential Revision: https://reviews.freebsd.org/D25872
This is a change in preparation for stopping to use lorder.sh (D26044) and
instead assume that we have a linker newer than ~1990. Without lorder.sh
duplicates end up being passed to the linker when building .so files and this
can result in duplicate symbol definition errors.
There is one minor change: libcompiler_rt.a will no longer provide
gcc_personality_v0 and instead we now only have it in libgcc_eh.a/libgcc_s.so.
This matches GCC's behaviour.
Reviewed By: emaste, cem
Differential Revision: https://reviews.freebsd.org/D26042
Should unbreak gcc build as reported by tinderbox:
lib/libc/gen/scandir.c:59:12: warning: 'alphasort_thunk' declared 'static' but never defined [-Wunused-function]
part of std::random_shuffle. These were split off at some point by
upstream, but I forgot to add them to our Makefile.
This should allow some ports which use std::random_shuffle to correctly
link again.
Reported by: thierry
PR: 248795
MFC after: 6 weeks
X-MFX-With: r364284
When files are read from .rc or .4th, verify_file is asked to
guess the severity (VE_TRY,VE_WANT,VE_MUST)
Reviewed by: stevek
MFC after: 1 week
Sponsored by: Juniper Networks
I have no idea what this does (and until now that it even existed), but
apparently it needs this entry changed for the MSG_TLSAPPDATA, since
it is kernel only.
Linking the full version of clang 11 results in errors similar to:
lld: error: /usr/src/contrib/llvm-project/clang/lib/StaticAnalyzer/Frontend/AnalysisConsumer.cpp:736:(.text._ZN5clang4ento22CreateAnalysisConsumerERNS_16CompilerInstanceE+0xE0): relocation R_MIPS_CALL16 out of range: 48920 is not in [-32768, 32767]; references operator new(unsigned long)
Add -mxgot to the compilation flags for llvm libraries to work around
this error. This may be too big of a hammer, but it can always be
refined later.
MFC after: 6 weeks
Introduce G_PART_ALIAS_SOLARIS_RESERVED, GPT_ENT_TYPE_SOLARIS_RESERVED et al.,
to make gpart show output more convenient on systems with illumos/openindiana
disks visible.
Submitted by: Juraj Lutter <otis AT sk.FreeBSD.org>
Reviewed by: bcr(manpages), delphij, myself
Differential Revision: https://reviews.freebsd.org/D26012
The standard uses 80+80 and 80p80 but nowhere 80_80.
Switch the latter to 80P80 for all the macros and comments refering
to #defined flags which I could find.
The only place we leave as 80p80 is the ifconfig command line arguments
as we spell them all in lower case.
Ideally we would use 80+80 for any interactions with the user and
80P80 for anything internal but let us not confuse parsers and
hence avoid the '+' in either case.
Reviewed by: adrian, gnn
MFC after: 2 weeks
Sponsored by: Rubicon Communications, LLC (d/b/a "Netgate")
Differential Revision: https://reviews.freebsd.org/D26001
flua does have some specific bits that will include luaconf.h, but the
definition of LUA_USE_DLOPEN for those won't matter. This belongs in liblua
instead.
To expand on my previous commit, which was a little sparse with details,
it's not really safe to allow LUA_USE_DLOPEN with host lib paths being used.
The host system could have an entirely different lua version and this could
cause us to crash and burn.
If we want to revive this later, we need to make sure to define c module
paths inside OBJDIR that are compiled against whatever version we've
bootstrapped.
Pointy hat: kevans
RFC5424 defines NILVALUE as '-'. Replace its usage with a macro and
separate out the fields to be more clear. fputs(3) is used in some
places to avoid hiding possible format string problems in a macro.
Reviewed by: cem, vangyzen (earlier version)
Sponsored by: Dell EMC
Use /usr not /usr/local for base system components.
Use /usr/lib/flua and /usr/share/flua (not lua) for consistency and to
avoid the possibility that other software accidentally finds our base
system modules.
Also drop the version from the path, as flua represents an unspecified
lua version that corresponds to the FreeBSD version it comes with.
LUA_USE_DLOPEN is not yet enabled because some additional changes are
needed wrt symbol visibility.
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D24605
This adds support for the Cortex-A76 and Neoverse-N1 PMU counters to pmc.
While here add more PMCR_IDCODE values and check the implementers code is
correct before setting the PMU type.
Reviewed by: bz, emaste (looks reasonable to me)
Sponsored by: Innovate UK
Differential Revision: https://reviews.freebsd.org/D25959
Apparently it was not exported, because scandir_b.c was not included
into libc SRCS. Export it with the CURRENT-13 version.
Also, because it was not exported before ino64, clean up
scandir-compat11.c.
PR: 248572
Reported by: Alex S <iwtcex@gmail.com>
Reviewed by: emaste
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D26020
libifconfig_sfp.h provides an API in libifconfig for querying SFP module
properties, operational status, and vendor strings, as well as descriptions
of the various fields, string conversions, and other useful helpers for
implementing user interfaces.
SFP module status is obtained by reading registers via an I2C interface.
Descriptions of these registers and the values therein have been collected
in a Lua table which is used to generate all the boilerplace C headers and
source files for accessing these values, their names, and descriptions.
The generated code is fully commented and readable.
This is the first use of libifconfig in ifconfig itself. For now, the
scope remains very limited. Over time, more of ifconfig will be replaced
with libifconfig.
Some minor changes to the formatting of ifconfig output have been made:
- Module memory hex dumps are indented one extra space as a result of using
hexdump(3) instead of a bespoke hex dump function.
- Media descriptions have an added two-character short-name in parenthesis.
- QSFP modules were incorrectly displaying TX bias current as power. Now
TX channels display bias current, and this change has been made for both
SFP and QSFP modules for consistency.
A Lua binding for libifconfig including this functionality is implemented
but has not been included in this commit. The plan is for it to be
committed after dynamic module loading has been enabled in flua.
Reviewed by: kp, melifaro
Relnotes: yes
Differential Revision: https://reviews.freebsd.org/D25494
required by both the static analyzer (MK_CLANG_FULL) and clang-format
(MK_CLANG_FORMAT). We could also invent yet another SRCS variant, but
that seems a bit overkill.
lib/libpam/modules/pam_exec/pam_exec.c:222:56: error: format specifies type 'char *' but the argument has type 'const void *' [-Werror,-Wformat]
if (asprintf(&envstr, "%s=%s", pam_item_env[i].name, item) < 0)
~~ ^~~~
On ELFv2, the overflow parameters in the stack frame are at a different offset
from sp than ELFv1. Adjust code to use the correct offset in all cases.
This had resulted in argv[8] and up being copied to the incorrect address
in the new context's initial stack frame.
This is not necessarily the only bug in this function, I need to do a full
review still and ensure the rest of the math is sane for ELFv2 stack frames.
Reported by: pherde (Probably. My notes are a bit unclear.)
Reviewed by: jhibbits (in irc)
Sponsored by: Tag1 Consulting, Inc.
The -I option (and hotkey) is reused for this. Skipping symbol resolution is
moved to the new -A option (and hotkey).
While arguably this violates POLA I think it's a change for the better.
ALso note the -I option was added in head.
Differential Revision: https://reviews.freebsd.org/D21658
Refactor to create devinfo_free_dev(). Call it to plug a memory leak
on two error paths in devinfo_init_devices().
Reported by: Coverity
MFC after: 2 weeks
Sponsored by: Dell EMC Isilon
Unlike lld, ld.bfd doesn't infer the emulation from the first object
file, but assumes its compiled in default for ld -r.
Differential Revision: https://reviews.freebsd.org/D25728
In lib/Makefile, we document the dependency with SUBDIR_DEPEND
For buildworld orchestration, just prebuild libregex if GOOGLETEST is
enabled. googletest will get built in a later pass.
gtest tests want to use \w ([[:alnum:]]) at the very least, which was
causing them to fail after r363679.
Start linking against libregex so that this shorthand is implemented.
PR: 248452
The entire patch-set is not yet mature enough for commit, but this usable
subset is generally enough for googletest to be happy with and mostly map to
some existing concepts, so they're not as invasive.
The specific changes included here are:
- Branching in BREs with \|
- \w and \W for [[:alnum:]] and [^[:alnum:]] respectively
- \s and \S for [[:space:]] and [^[:space:]] respectively
- Additional quantifiers in BREs, \? and \+ (self-explanatory)
There's some #ifdef'd out work for allowing empty branches as a match-all.
This is a feature that's under assessment... future work will determine
how standard this behavior is and act accordingly.
The constant seems to exists on MacOS X >= 10.8.
Requested by: swills
Reviewed by: allanjude, kevans
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D25933
We bootstrap this file to allow compiling FreeBSD on Linux systems since
some boostrap tools use setmode(). Unfortunately, glibc's sys/stat.h
declares a non-static getumask() function (which is unimplemented!) and
that conflicts with the local getumask() function. To work around this
simply use a different name here.
Reviewed By: brooks, emaste
Differential Revision: https://reviews.freebsd.org/D25929
GCC's cpp was exiting immediately when it failed to find requested
includes (<ncurses_cfg.h> and <ncurses_defs.h>). clang-cpp emitted an
error for the missing header files but continued processing the file
(thus not honoring any macros defined in the missing headers).
Arguably, the awk script is buggy since it doesn't check the return
value of the command it executes.
Reviewed by: kevans
Differential Revision: https://reviews.freebsd.org/D25731
RISC-V doesn't support floating-point exceptions.
RISC-V Instruction Set Manual: Volume I: User-Level ISA, 11.2 Floating-Point
Control and Status Register: "As allowed by the standard, we do not support
traps on floating-point exceptions in the base ISA, but instead require
explicit checks of the flags in software. We considered adding branches
controlled directly by the contents of the floating-point accrued exception
flags, but ultimately chose to omit these instructions to keep the ISA simple."
We still need these functions, because some applications (notably Perl) call
them, but we cannot provide a meaningful implementation.
Sponsored by: Axiado
Differential Revision: https://reviews.freebsd.org/D25740
In IEEE 1003.1-2008 [1] and earlier revisions, BRE/ERE grammar allows for
any character to be escaped, but "ORD_CHAR preceded by an unescaped
<backslash> character [gives undefined results]".
Historically, we've interpreted an escaped ordinary character as the
ordinary character itself. This becomes problematic when some extensions
give special meanings to an otherwise ordinary character
(e.g. GNU's \b, \s, \w), meaning we may have two different valid
interpretations of the same sequence.
To make this easier to deal with and given that the standard calls this
undefined, we should throw an error (EESCAPE) if we run into this scenario
to ease transition into a state where some escaped ordinaries are blessed
with a special meaning -- it will either error out or have extended
behavior, rather than have two entirely different versions of undefined
behavior that leave the consumer of regex(3) guessing as to what behavior
will be used or leaving them with false impressions.
This change bumps the symbol version of regcomp to FBSD_1.6 and provides the
old escape semantics for legacy applications, just in case one has an older
application that would immediately turn into a pumpkin because of an
extraneous escape that's embedded or otherwise critical to its operation.
This is the final piece needed before enhancing libregex with GNU extensions
and flipping the switch on bsdgrep.
[1] http://pubs.opengroup.org/onlinepubs/9699919799.2016edition/
PR: 229925 (exp-run, courtesy of antoine)
Differential Revision: https://reviews.freebsd.org/D10510
