This patch removes conditionals on __ASSUME_O_CLOEXEC, and on
O_CLOEXEC being defined, in sysdeps/unix/sysv/linux/, now that
O_CLOEXEC support can be unconditionally assumed.
The patch is conservative in what it changes and further followup
cleanups may be possible. It may be possible to remove dl-opendir.c,
but the patch does not do so, just removing a redundant undefine and
redefine of __ASSUME_O_CLOEXEC. Also, __ASSUME_O_CLOEXEC is defined
unconditionally for Hurd as well as Linux. Thus, if we decide that
O_CLOEXEC support is a required feature of any glibc port, we could
remove __ASSUME_O_CLOEXEC and all conditionals on it throughout glibc,
rather than just cleaning up sysdeps/unix/sysv/linux/.
Tested x86_64 that the disassembly of installed shared libraries is
unchanged by this patch.
* sysdeps/unix/sysv/linux/dl-opendir.c (__ASSUME_O_CLOEXEC): Do
not undefine and redefine.
* sysdeps/unix/sysv/linux/getsysstats.c (__get_nprocs)
[O_CLOEXEC]: Make code unconditional.
(__get_nprocs) [!O_CLOEXEC]: Remove conditional code.
* sysdeps/unix/sysv/linux/shm_open.c: Do not include
<kernel-features.h>.
[O_CLOEXEC && !__ASSUME_O_CLOEXEC] (have_o_cloexec): Remove
conditional variable definition.
(shm_open) [O_CLOEXEC]: Make code unconditional.
(shm_open) [!O_CLOEXEC || !__ASSUME_O_CLOEXEC]: Remove conditional
code.
This patch moves the USE_REGPARMS define from the toplevel
configure.ac to sysdeps/i386/configure.ac.
Tested x86 that the disassembly of installed shared libraries is
unchanged by this patch.
* configure.ac (USE_REGPARMS): Don't define here.
* configure: Regenerated.
* sysdeps/i386/configure.ac (USE_REGPARMS): Define here.
* sysdeps/i386/configure: Regenerated.
One piece of architecture-specific code in the main configure.ac is
the powerpc test that can define BROKEN_PPC_ASM_CR0. There's no need
to move this to a sysdeps configure script, or to work out what bug it
was testing in May 1998 to see if it's still relevant, since nothing
in the source tree now uses the results of this test. Thus, this
patch just removes the test in question.
Not tested.
* configure.ac (libc_cv_c_asmcr0_bug): Remove configure test.
* configure: Regenerated.
* config.h.in (BROKEN_PPC_ASM_CR0): Remove macro.
This patch makes non-ex-ports architectures set base_machine and
machine based on the original configured machine value in preconfigure
fragments, like ex-ports architectures, rather than in the toplevel
configure.ac.
Tested x86 that the disassembly of installed shared libraries is
unchanged by the patch.
* configure.ac (base_machine): Do not set specially for particular
machines here.
* configure: Regenerated.
* sysdeps/powerpc/preconfigure: Move machine and base_machine
settings from configure.ac.
* sysdeps/i386/preconfigure: New file.
* sysdeps/s390/preconfigure: Likewise.
* sysdeps/sh/preconfigure: Likewise.
* sysdeps/sparc/preconfigure: Likewise.
This patch updates the timezone code from tzcode 2014e (the previous
version used was 2013i).
Tested x86_64.
* timezone/checktab.awk: Update from tzcode 2014e.
* timezone/private.h: Likewise.
* timezone/tzfile.h: Likewise.
* timezone/zdump.c: Likewise.
* timezone/zic.c: Likewise.
This patch removes the __ASSUME_XFS_RESTRICTED_CHOWN macro, now it can
be presumed to be defined unconditionally. I'm not sure if what's
left of __statfs_chown_restricted is actually useful (if not, a
followup could remove it), but I left it there to keep the patch
conservative and avoid changing the code generated for glibc.
Tested x86_64 that the disassembly of installed shared libraries is
unchanged by the patch.
* sysdeps/unix/sysv/linux/kernel-features.h
(__ASSUME_XFS_RESTRICTED_CHOWN): Remove macro.
* sysdeps/unix/sysv/linux/pathconf.c (__statfs_chown_restricted)
[__ASSUME_XFS_RESTRICTED_CHOWN]: Make code unconditional.
(__statfs_chown_restricted) [!__ASSUME_XFS_RESTRICTED_CHOWN]:
Remove conditional code.
Add support for the new HWCAP2 values for ARMv8 added in the
3.15 kernel. Tested using QEMU which supports these extensions.
ChangeLog:
2014-06-25 Will Newton <will.newton@linaro.org>
* sysdeps/unix/sysv/linux/arm/dl-procinfo.c
(_dl_arm_cap_flags): Add HWCAP2 values.
* sysdeps/unix/sysv/linux/arm/dl-procinfo.h
(_DL_HWCAP_COUNT): Increase to 37.
(_DL_HWCAP_LAST): New define.
(_DL_HWCAP2_LAST): New define.
(_dl_procinfo): Add support for printing
AT_HWCAP2 entries.
(_dl_string_hwcap): Use _dl_hwcap_string.
This patch updates README to remove a mention of the ports directory.
It also adds a NEWS item for the merge of ports into the main sysdeps
tree (I think it's NEWS-worthy, although not strictly a user-visible
feature).
Other remaining ports references to resolve: a comment in
manual/signal.texi (not giving a literal path, but maybe should change
anyway); a comment in config.h.in (path should be updated);
scripts/list-sources.sh (appears to date back to ports being a
separate repository).
* README: Do not mention ports directory.
This patch removes the __ASSUME_UTIMENSAT macro, now it can be
unconditionally assumed to be true.
This shows that the only live uses of __ASSUME_UTIMES are in utimes.c
and they are only live for hppa. I intend a followup patch to make
__ASSUME_UTIMES into an hppa-specific macro (not used or defined
outside sysdeps/unix/sysv/linux/hppa/).
Tested x86_64 that the disassembly of installed shared libraries is
unchanged by this patch.
* sysdeps/unix/sysv/linux/kernel-features.h (__ASSUME_UTIMENSAT):
Remove macro.
* sysdeps/unix/sysv/linux/futimes.c: Do not include
<kernel-features.h>.
[__NR_utimensat && !__ASSUME_UTIMENSAT] (miss_utimensat): Remove
conditional variable definition.
(__futimes): Update comment.
(__futimes) [__ASSUME_UTIMENSAT]: Make code unconditional.
(__futimes) [!__ASSUME_UTIMENSAT]: Remove conditional code.
This patch fixes spurious underflows from exp10 for arguments near 0
(part of bug 16560; that bug also includes spurious underflows from
exp2, which are not fixed by this patch). The problem is underflows
in the internal computation converting the exp10 argument to arguments
for exp (with extra precision), and the fix is simply to return 1
early for arguments near enough to 0 (just as arguments with large
enough magnitude have their own overflow / underflow logic at the
start of the function).
Tested x86_64 and x86 and ulps updated accordingly; also tested for
powerpc32 and mips64 to validate the ldbl-128ibm and ldbl-128 changes.
[BZ #16560]
* sysdeps/ieee754/dbl-64/e_exp10.c (__ieee754_exp10): Return 1 for
arguments close to 0.
* sysdeps/ieee754/ldbl-128/e_exp10l.c (__ieee754_exp10l):
Likewise.
* sysdeps/ieee754/ldbl-128ibm/e_exp10l.c (__ieee754_exp10l):
Likewise.
* math/auto-libm-test-in: Add more tests of exp10.
* math/auto-libm-test-out: Regenerated.
* sysdeps/x86_64/fpu/libm-test-ulps: Update.
This patch removes the __ASSUME_COMPLETE_READV_WRITEV
kernel-features.h macro, now that it can be unconditionally assumed to
be true. (The relevant kernel feature was added some time between 2.0
and 2.2, and this macro is only used in sysdeps/unix/sysv/linux/.)
Tested x86_64 that the disassembly of installed shared libraries is
unchanged by this patch.
* sysdeps/unix/sysv/linux/kernel-features.h
(__ASSUME_COMPLETE_READV_WRITEV): Remove macro.
* sysdeps/unix/sysv/linux/readv.c: Do not include
<kernel-features.h>.
[!__ASSUME_COMPLETE_READV_WRITEV]: Remove conditional code.
[!UIO_FASTIOV] (UIO_FASTIOV): Remove macro.
(__libc_readv) [__ASSUME_COMPLETE_READV_WRITEV]: Make code
unconditional.
(__libc_readv) [!__ASSUME_COMPLETE_READV_WRITEV]: Remove
conditional code.
* sysdeps/unix/sysv/linux/writev.c: Do not include
<kernel-features.h>.
[!__ASSUME_COMPLETE_READV_WRITEV]: Remove conditional code.
[!UIO_FASTIOV] (UIO_FASTIOV): Remove macro.
(__libc_writev) [__ASSUME_COMPLETE_READV_WRITEV]: Make code
unconditional.
(__libc_writev) [!__ASSUME_COMPLETE_READV_WRITEV]: Remove
conditional code.
Partial merge from gnulib which fixes a number of -Wundef warnings.
The parts that differ from gnulib are the header comment, use of
__glibc_unlikely, a #define of __secure_getenv and the use of tabs.
The majority of the patch is cosmetic comment changes, the only runtime
change is an abort if an unknown kind is passed to __gen_tempname.
ChangeLog:
2014-06-25 Will Newton <will.newton@linaro.org>
* sysdeps/posix/tempname.c: Merge from gnulib, cosmetic
comment changes throughout the file. Remove checks
for HAVE_*_H definitions that are not required.
(__gen_tempname): Call abort if an unknown kind value is
passed.
This patch fixes bug 16539, spurious underflow exceptions from x86 /
x86-64 expm1l. The problem is that the computation of a base-2
exponent with extra precision involves spurious underflows for
arguments that are small but not subnormal, so a check is added to
just return the argument in those cases. (If the argument *is*
subnormal, underflowing is correct and the existing code will always
underflow, so it suffices to keep using the existing code in that
case; some expm1 implementations have a bug (bug 16353) with missing
underflow exceptions, but I don't think there's such a bug in this
particular version.)
Tested x86_64 and x86; no ulps updates needed.
(auto-libm-test-out diffs omitted below.)
[BZ #16539]
* sysdeps/i386/fpu/e_expl.S (IEEE754_EXPL) [USE_AS_EXPM1L]: Just
return the argument for normal arguments with exponent below -64.
* sysdeps/x86_64/fpu/e_expl.S (IEEE754_EXPL) [USE_AS_EXPM1L]:
Likewise.
* math/auto-libm-test-in: Add another test of expm1.
* math/auto-libm-test-out: Regenerated.
This patch fixes bug 16287, spurious underflows from ldbl-128 erfl
arising from it calling erfcl for arguments with absolute value at
least 1.0, although for large positive arguments erfcl correctly
underflows but erfl shouldn't. The fix is simply to avoid calling
erfcl, and just return 1, for arguments above a cut-off large enough
that erfl correctly rounds to-nearest as 1 but not so large that erfcl
underflows.
Tested mips64. Also tested x86_64 and x86 to confirm the new tests
(taken from the tests of erfc) don't cause any problems there; no ulps
updates needed.
[BZ #16287]
* sysdeps/ieee754/ldbl-128/s_erfl.c (__erfl): Return 1 without
calling __erfcl for arguments at least 16.
* math/auto-libm-test-in: Add more tests of erf.
* math/auto-libm-test-out: Regenerated.
Continuing the process of making non-ex-ports architectures follow the
preferred sysdeps practices followed by ex-ports architectures - that
is, putting things in architecture-specific sysdeps files rather than
having architecture-specific cases in architecture-independent files -
this patch moves architecture cases out of
sysdeps/unix/sysv/linux/configure.ac into (new or existing) configure
fragments for each architecture. (In the case of the
arch_minimum_kernel setting for x32,
sysdeps/unix/sysv/linux/x86_64/x32/configure already has such a
setting so the setting in sysdeps/unix/sysv/linux/configure.ac was a
duplicate that could just be removed - though I haven't tested for
x32.)
Tested for x86_64 and x86 that the patch causes no changes to the
installed shared libraries or ldd (or any part of the installation
except for the parts that always change because the files contain
timestamps - nscd and static libraries).
* sysdeps/unix/sysv/linux/configure.ac: Remove cases for
individual architectures.
* sysdeps/unix/sysv/linux/configure: Regenerated.
* sysdeps/unix/sysv/linux/i386/configure.ac: New file.
* sysdeps/unix/sysv/linux/i386/configure: New generated file.
* sysdeps/unix/sysv/linux/powerpc/configure.ac
(ldd_rewrite_script): Define variable.
* sysdeps/unix/sysv/linux/powerpc/configure: Regenerated.
* sysdeps/unix/sysv/linux/powerpc/powerpc32/configure.ac: New
file.
* sysdeps/unix/sysv/linux/powerpc/powerpc32/configure: New
generated file.
* sysdeps/unix/sysv/linux/s390/configure.ac: New file.
* sysdeps/unix/sysv/linux/s390/configure: New generated file.
* sysdeps/unix/sysv/linux/sh/configure.ac: New file.
* sysdeps/unix/sysv/linux/sh/configure: New generated file.
* sysdeps/unix/sysv/linux/sparc/configure.ac: New file.
* sysdeps/unix/sysv/linux/sparc/configure: New generated file.
* sysdeps/unix/sysv/linux/x86_64/configure.ac: New file.
* sysdeps/unix/sysv/linux/x86_64/configure: New generated file.
Improve fesetenv to use an optimized implementation similar to
feupdateenv.
2014-06-24 Wilco <wdijkstr@arm.com>
* sysdeps/arm/fesetenv.c (fesetenv): Optimize implementation.
This patch rewrites feupdateenv to improve performance by avoiding
unnecessary FPSCR reads/writes. It fixes bug 16918 by passing the
correct return value.
2014-06-24 Wilco <wdijkstr@arm.com>
[BZ #16918]
* sysdeps/arm/feupdateenv.c (feupdateenv):
Rewrite to reduce FPSCR accesses and fix return value.
rather than duplicating functionality. To make this work for softfp builds,
ensure functions in fenv_private are not conditionally compiled.
2014-06-24 Wilco <wdijkstr@arm.com>
* sysdeps/arm/fegetround.c (fegetround): Call get_rounding_mode.
* sysdeps/arm/feholdexcpt.c (feholdexcept): Call libc_feholdexcept_vfp.
* sysdeps/arm/fesetround.c (fesetround): Call libc_fesetround_vfp.
* sysdeps/arm/fgetexcptflg.c (fegetexceptflag):
Call libc_fetestexcept_vfp.
* sysdeps/arm/ftestexcept.c (fetestexcept): Call libc_fetestexcept_vfp.
* sysdeps/arm/fenv_private.h: Move libc_*_vfp functions outside of
__SOFTFP__ ifdef so that they can be built for softfp.
The first argument of elision_adapt and that of ELISION_*LOCK have
different signs since __elision_rwcount is signed char * and the
argument of elision_adapt is uint8_t *. Modified elision_adapt to
accept signed char * instead of uint8_t *.
This patch fixes bug 16354, spurious underflows from cosh when a tiny
argument is passed to expm1 and expm1 correctly underflows although
the final result of cosh should be 1. As noted in that bug, some
cases are latent because of expm1 implementations not raising
underflow (bug 16353), but all the implementations are fixed
similarly. They already contained checks for tiny arguments, but the
checks were too late to avoid underflow from expm1 (although they
would avoid underflow from subsequent squaring of the result of
expm1); they are moved before the expm1 calls.
The thresholds used for considering arguments tiny are not
particularly consistent in how they relate to the precision of the
floating-point format in question. They are, however, all sufficient
to ensure that the round-to-nearest result of cosh is indeed 1 below
the threshold (although sometimes they are smaller than necessary).
But the previous logic did not return 1, but the previously computed 1
+ expm1(abs(x)) value. And the thresholds in the ldbl-128 and
ldbl-128ibm code (0x1p-71L - I suspect 0x3f8b was intended in the code
instead of 0x3fb8 - and (roughly) 0x1p-55L) are not sufficient for
that value to be 1. So by moving the test for tiny arguments, and
consequently returning 1 directly now the expm1 value hasn't been
computed by that point, this patch also fixes bug 17061, the (large
number of ulps) inaccuracy for small arguments in those
implementations. Tests for that bug are duly added.
Tested x86_64 and x86 and ulps updated accordingly. Also tested for
mips64 and powerpc32 to validate the ldbl-128 and ldbl-128ibm changes.
[BZ #16354]
[BZ #17061]
* sysdeps/ieee754/dbl-64/e_cosh.c (__ieee754_cosh): Check for
small arguments before calling __expm1.
* sysdeps/ieee754/flt-32/e_coshf.c (__ieee754_coshf): Check for
small arguments before calling __expm1f.
* sysdeps/ieee754/ldbl-128/e_coshl.c (__ieee754_coshl): Check for
small arguments before calling __expm1l.
* sysdeps/ieee754/ldbl-128ibm/e_coshl.c (__ieee754_coshl):
Likewise.
* sysdeps/ieee754/ldbl-96/e_coshl.c (__ieee754_coshl): Likewise.
* math/auto-libm-test-in: Add more cosh tests. Do not allow
spurious underflow for some cosh tests.
* math/auto-libm-test-out: Regenerated.
* sysdeps/i386/fpu/libm-test-ulps: Update.
This patch fixes bug 17050, missing errno setting for y1 overflow (for
small positive arguments). An appropriate check is added for overflow
directly in the __ieee754_y1 implementation, similar to the check
present for yn (doing it there rather than in the wrapper also avoids
yn needing to repeat the check when called for order 1 or -1 and it
uses __ieee754_y1).
Tested x86_64 and x86; no ulps update needed. Also tested for mips64
to verify the ldbl-128 fix (the ldbl-128ibm code just #includes the
ldbl-128 file).
[BZ #17050]
* sysdeps/ieee754/dbl-64/e_j1.c: Include <errno.h>.
(__ieee754_y1): Set errno if return value overflows.
* sysdeps/ieee754/flt-32/e_j1f.c: Include <errno.h>.
(__ieee754_y1f): Set errno if return value overflows.
* sysdeps/ieee754/ldbl-128/e_j1l.c: Include <errno.h>.
(__ieee754_y1l): Set errno if return value overflows.
* sysdeps/ieee754/ldbl-96/e_j1l.c: Include <errno.h>.
(__ieee754_y1l): Set errno if return value overflows.
* math/auto-libm-test-in: Add more tests of y0, y1 and yn.
* math/auto-libm-test-out: Regenerated.
This patch enables testing of cpow in all rounding modes using
ALL_RM_TEST. There were two reasons this was previously deferred:
* MPC has complicated rounding-mode-dependent rules for the signs of
exact zero real or imaginary parts in the result of mpc_pow. Annex
G does not impose any such requirements and I don't think glibc
should try to implement any particular logic here. This patch adds
support for gen-auto-libm-tests passing the IGNORE_ZERO_INF_SIGN
flag to libm-test.inc.
* Error accumulations in some tests in non-default rounding modes
exceed the maximum error permitted in libm-test.inc. This patch
marks the problem tests with xfail-rounding. (It might be possible
to reduce the accumulations a bit by using round-to-nearest when
cpow calls clog, but I don't think there's much point; the
implementation approach for cpow is fundamentally deficient, as
discussed in the existing bug for cpow inaccuracy which can
reasonably be considered to cover these less-inaccurate cases as
well. It's possible that the test "cpow 2 0 10 0" will also need
xfail-rounding on some platforms.)
Tested x86_64 and x86 and ulps updated accordingly.
* math/gen-auto-libm-tests.c: Document use of
ignore-zero-inf-sign.
(input_flag_type): Add value flag_ignore_zero_inf_sign.
(input_flags): Add ignore-zero-inf-sign.
(output_for_one_input_case): Handle flag_ignore_zero_inf_sign.
* math/gen-libm-test.pl (generate_testfile): Handle
ignore-zero-inf-sign.
* math/auto-libm-test-in: Mark some cpow tests with
ignore-zero-inf-sign and some with xfail-rounding.
* math/auto-libm-test-out: Regenerated.
* math/libm-test.inc (cpow_test): Use ALL_RM_TEST.
* sysdeps/i386/fpu/libm-test-ulps: Update.
* sysdeps/x86_64/fpu/libm-test-ulps: Likewise.
This patch fixes bug 16315, bad pow handling of overflow/underflow in
non-default rounding modes. Tests of pow are duly converted to
ALL_RM_TEST to run all tests in all rounding modes.
There are two main issues here. First, various implementations
compute a negative result by negating a positive result, but this
yields inappropriate overflow / underflow values for directed
rounding, so either overflow / underflow results need recomputing in
the correct sign, or the relevant overflowing / underflowing operation
needs to be made to have a result of the correct sign. Second, the
dbl-64 implementation sets FE_TONEAREST internally; in the overflow /
underflow case, the result needs recomputing in the original rounding
mode.
Tested x86_64 and x86 and ulps updated accordingly.
[BZ #16315]
* sysdeps/i386/fpu/e_pow.S (__ieee754_pow): Ensure possibly
overflowing or underflowing operations take place with sign of
result.
* sysdeps/i386/fpu/e_powf.S (__ieee754_powf): Likewise.
* sysdeps/i386/fpu/e_powl.S (__ieee754_powl): Likewise.
* sysdeps/ieee754/dbl-64/e_pow.c: Include <math.h>.
(__ieee754_pow): Recompute overflowing and underflowing results in
original rounding mode.
* sysdeps/x86/fpu/powl_helper.c: Include <stdbool.h>.
(__powl_helper): Allow negative argument X and scale negated value
as needed. Avoid passing value outside [-1, 1] to f2xm1.
* sysdeps/x86_64/fpu/e_powl.S (__ieee754_powl): Ensure possibly
overflowing or underflowing operations take place with sign of
result.
* sysdeps/x86_64/fpu/multiarch/e_pow.c [HAVE_FMA4_SUPPORT]:
Include <math.h>.
* math/auto-libm-test-in: Add more tests of pow.
* math/auto-libm-test-out: Regenerated.
* math/libm-test.inc (pow_test): Use ALL_RM_TEST.
(pow_tonearest_test_data): Remove.
(pow_test_tonearest): Likewise.
(pow_towardzero_test_data): Likewise.
(pow_test_towardzero): Likewise.
(pow_downward_test_data): Likewise.
(pow_test_downward): Likewise.
(pow_upward_test_data): Likewise.
(pow_test_upward): Likewise.
(main): Don't call removed functions.
* sysdeps/i386/fpu/libm-test-ulps: Update.
* sysdeps/x86_64/fpu/libm-test-ulps: Likewise.
This patch adds a generic implementation of HAVE_RM_CTX using standard
fenv calls. As a result math functions using SET_RESTORE_ROUND* macros
do not suffer from a large slowdown on targets which do not implement
optimized libc_fe*_ctx inline functions. Most of the libc_fe* inline
functions are now unused and could be removed in the future (there are
a few math functions left which use a mixture of standard fenv calls
and libc_fe* inline functions - they could be updated to use
SET_RESTORE_ROUND or improved to avoid expensive fenv manipulations
across just a few FP instructions).
libc_feholdsetround*_noex_ctx is added to enable better optimization of
SET_RESTORE_ROUND_NOEX* implementations.
Performance measurements on ARM and x86 of sin() show significant gains
over the current default, fairly close to a highly optimized fenv_private:
ARM x86
no fenv_private : 100% 100%
generic HAVE_RM_CTX : 250% 350%
fenv_private (CTX) : 250% 450%
2014-06-23 Will Newton <will.newton@linaro.org>
Wilco <wdijkstr@arm.com>
* sysdeps/generic/math_private.h: Add generic HAVE_RM_CTX
implementation. Include get-rounding-mode.h.
[!HAVE_RM_CTX]: Define HAVE_RM_CTX to zero.
[!libc_feholdsetround_noex_ctx]: Define
libc_feholdsetround_noex_ctx.
[!libc_feholdsetround_noexf_ctx]: Define
libc_feholdsetround_noexf_ctx.
[!libc_feholdsetround_noexl_ctx]: Define
libc_feholdsetround_noexl_ctx.
(libc_feholdsetround_ctx): New function.
(libc_feresetround_ctx): New function.
(libc_feholdsetround_noex_ctx): New function.
(libc_feresetround_noex_ctx): New function.
This patch updates glibc headers for changes / new definitions in
Linux 3.15. In the course of my review I noticed that
IPV6_PMTUDISC_INTERFACE was absent from glibc despite the inclusion of
IP_PMTUDISC_INTERFACE; I added it along with IP_PMTUDISC_OMIT and
IPV6_PMTUDISC_OMIT. I did not add FALLOC_FL_NO_HIDE_STALE given the
kernel header comment that it is reserved.
Tested x86_64.
* sysdeps/unix/sysv/linux/bits/fcntl-linux.h [__USE_GNU]
(FALLOC_FL_COLLAPSE_RANGE): New macro.
[__USE_GNU] (FALLOC_FL_ZERO_RANGE): Likewise.
* sysdeps/unix/sysv/linux/bits/in.h (IP_PMTUDISC_OMIT): Likewise.
(IPV6_PMTUDISC_INTERFACE): Likewise.
(IPV6_PMTUDISC_OMIT): Likewise.
