Write errors to stdout and not stderr in nptl/tst-setuid3.c

nptl/tst-setuid3.c was using the `err' and `errx' functions to write
error messages. This wrote to stderr instead of the preferred stdout.
tilegx: optimize string copy_byte() internal function

We can use one "shufflebytes" instruction instead of 3 "bfins"
instructions to optimize the string functions.
tilegx: provide optimized strnlen, strstr, and strcasestr

strnlen() is based on the existing tile strlen() with length
checking added.  It speeds up by up to 5x, but on average across
the benchtest corpus by around 35%.  No regressions are seen.

strstr() does 8-byte aligned loads and compares using a 2-byte
filter on the first two bytes of the needle and then testing
the remaining bytes in needle using memcmp().  It speeds up
about 5x in the best case (for "found" needles), about 2x looking
at benchtest as a whole, with some slowdowns as much as 45%.
on a few cases (including the "fail" case for 128KB search).

strcasestr() is based on strstr() but uses a SIMD tolower
routine to convert 8-bytes to lower case in 5 instructions.
It also uses a 2-byte filter and then strncasecmp() for the
remaining bytes.  strncasecmp() is not optimized for SIMD, so
there is futher room for improvement.  However, it is still up
to 16x faster for "found" needles, averaging 2x faster on the
whole corpus of benchtests.  It does slow down by up to 35%
on a few cases, similarly to strstr().
tile: add support for _SC_LEVEL*CACHE* sysconf() queries
tile: optimize memcmp

Customize memcmp.c for tile, using similar tricks from memcpy:

- replace MERGE macro with dblalign.
- replace memcmp_bytes function with revbytes.
- use __glibc_likely.
- use post-increment addressing.

The schedule is still not perfect: the compiler is not hoisting
code above the comparison branch, which could save a bundle or two.
memcmp speeds up by 30-40% on shorter aligned tests in benchtest,
with some tests with unaligned lengths taking a small performance hit.
tile: make the prolog of clone() more conformant

With this change we properly set up the frame first, and tear
it down last, doing argument checking only when the frame is set up.
tile: add clock_gettime support via vDSO
tile: fix copyright header blocks in just-committed files

I accidentally committed versions not following the conventions.
powerpc: remove linux lowlevellock.h

This patch remove the powerpc specific lowlevellock.h and adjust some
implementation that rely on __lll_[rel/acq]_instr defines.
Move some chown / lchown / fchown definitions to syscalls.list (bug 14138).

Continuing the move of syscall definitions to syscalls.list, where the
removal of support for old kernel versions has made this possible,
this patch moves various definitions of chown, lchown and fchown.

In most cases the need for special syscalls.list entries (rather than
existing generic ones) is because these architectures use chown32,
lchown32 and fchown32 as syscall names.  Some architectures also have
symbol versioning compatibility for older versions of chown having
been equivalent to lchown.

In the case of powerpc, chown.c (providing the chown@@GLIBC_2.1
default version) is replaced by a syscalls.list entry (for powerpc32;
powerpc64 has no need for this because of its more recent minimum
symbol version, so can just use the entry in
sysdeps/unix/syscalls.list), but lchown.S is left as-is because it
provides the compat version of chown as an actual alias for __lchown,
which is not yet supported by syscalls.list.  This file can be removed
once such aliases are supported in syscalls.list.

	[BZ #14138]
	* sysdeps/unix/sysv/linux/arm/fchown.c: Remove file.
	* sysdeps/unix/sysv/linux/arm/lchown.c: Likewise.
	* sysdeps/unix/sysv/linux/m68k/fchown.c: Likewise.
	* sysdeps/unix/sysv/linux/m68k/lchown.c: Likewise.
	* sysdeps/unix/sysv/linux/powerpc/chown.c: Likewise.
	* sysdeps/unix/sysv/linux/arm/syscalls.list (lchown): Add syscall.
	(fchown): Likewise.
	* sysdeps/unix/sysv/linux/m68k/syscalls.list (lchown): Likewise.
	(fchown): Likewise.
	* sysdeps/unix/sysv/linux/powerpc/powerpc32/syscalls.list (chown):
	Likewise.
Support and use mixed compat/non-compat aliases in syscalls.list.

This patch enables syscalls.list entries to specify both compat and
non-compat symbol versions for the same syscall definition, making use
of this for setrlimit / chown / lchown where the inability to specify
such aliases showed up in the course of work on bug 14138.

The change to make-syscalls.sh is minimal: adding a SHARED conditional
on the compat_symbol calls.  It remains the case that if a compat
symbol version is specified, the syscall is only built for the shared
library at all if an explicit symbol version is given for a non-compat
symbol (so it's necessary to specify "lchown@@GLIBC_2.0
chown@GLIBC_2.0" rather than just "lchown chown@GLIBC_2.0").  It also
remains the case, as already commented in make-syscalls.sh, that no
SHLIB_COMPAT conditionals are generated, so there would be problems if
the same syscalls.list file, with compat symbols, were used for both
configurations that should have those symbols and configurations for
which they should be conditioned out with SHLIB_COMPAT.

Tested for x86.

	* sysdeps/unix/make-syscalls.sh (emit_weak_aliases): Condition
	compat_symbol calls on [SHARED].
	* sysdeps/unix/sysv/linux/powerpc/lchown.S: Remove file.
	* sysdeps/unix/sysv/linux/i386/syscalls.list (oldsetrlimit):
	Remove.
	(setrlimit): Add setrlimit@GLIBC_2.0 alias.
	* sysdeps/unix/sysv/linux/m68k/m680x0/syscalls.list
	(oldsetrlimit): Remove.
	(setrlimit): Add setrlimit@GLIBC_2.0 alias.
	* sysdeps/unix/sysv/linux/powerpc/powerpc32/syscalls.list
	(lchown): New syscall entry.
	(oldsetrlimit): Remove.
	(setrlimit): Add setrlimit@GLIBC_2.0 alias.
	* sysdeps/unix/sysv/linux/s390/s390-32/syscalls.list
	(oldsetrlimit): Remove.
	(setrlimit): Add setrlimit@GLIBC_2.0 alias.