Use the per-feature check flags for the unwinding feature in order to
correctly compile the test-all, libunwind and libunwind-debug-frame
feature checks.

Tested on x86_64, ARMv7 and ARMv8 with and without LIBUNWIND_DIR set in
'make -C tools/perf'
Signed-off-by: NJean Pihet <jean.pihet@linaro.org>
Acked-by: NIngo Molnar <mingo@kernel.org>
Acked-by: NJiri Olsa <jolsa@redhat.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: linaro-kernel@lists.linaro.org
Cc: patches@linaro.org
Link: http://lkml.kernel.org/r/1386678244-13535-3-git-send-email-jean.pihet@linaro.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

We use -fstack-protector-all option to enable stack protecting for all
available functions. There's no reason for enabling -Wstack-protector to
get warning for unprotected functions.

Removing stackprotector feature check which was used to enable the
-Wstack-protector option.
Signed-off-by: NJiri Olsa <jolsa@redhat.com>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/1386076182-14484-2-git-send-email-jolsa@redhat.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

Set feature-libunwind-debug-frame. We don't want it in
CORE_FEATURE_TESTS because it's not the generic case, but we
need to set it in the !feature-libunwind case.

Also, because x86 distributions typically don't have
dwarf_find_debug_frame() unwinding method:

  test-libunwind-debug-frame.c:(.text+0x31): undefined reference to `_Ux86_64_dwarf_find_debug_frame'

Restrict this new API to ARM for the time being.

With this patch test-all.c works again, so repeat perf builds
are  fast again:

  comet:~/tip> perf stat --null --repeat 5 make -C tools/perf/
  [...]

       0,452899660 seconds time elapsed                                          ( +-  0,11% )

While with before it was:

  comet:~/tip> perf stat --null --repeat 5 make -C tools/perf/
  [...]

       1,674001829 seconds time elapsed                                          ( +-  0,16% )

[ Includes fix to config/feature-checks/Makefile from Will Deacon. ]
Tested-by: NWill Deacon <will.deacon@arm.com>
Tested-by: NJean Pihet <jean.pihet@linaro.org>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Arnaldo Carvalho de Melo <acme@infradead.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/n/tip-scsoctqzmou3rpkixCHezy9e@git.kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

If the OS does not have timerfd support (e.g., older OS'es like RHEL5)
disable perf kvm stat live.
Signed-off-by: NDavid Ahern <dsahern@gmail.com>
Reviewed-by: NJiri Olsa <jolsa@redhat.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1383064996-20933-2-git-send-email-dsahern@gmail.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

Use -lunwind-x86 instead of -lunwind-x86_64 for 32-bit build.
Signed-off-by: NAdrian Hunter <adrian.hunter@intel.com>
Acked-by: NJiri Olsa <jolsa@redhat.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1383313899-15987-5-git-send-email-adrian.hunter@intel.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

Setting EXTRA_CFLAGS=-m32 did not work because it was not passed around.
Signed-off-by: NAdrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1383313899-15987-4-git-send-email-adrian.hunter@intel.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

Namhyung Kim noticed that the autodep .d file inclusion rule was
unnecessarily complicated:

  > > +-include *.d */*.d
  >
  > Hmm.. this */*.d part is really needed?

Only include *.d files.
Reported-by: NNamhyung Kim <namhyung@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Signed-off-by: NIngo Molnar <mingo@kernel.org>
Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

Namhyung Kim noticed that the stackprotector testcase was incomplete:

  > The flag being checked should be -"W"stack-protector instead of
  > -"f"stack-protector.  And the gcc manpage says that -Wstack-protector is
  > only active when -fstack-protector is active.  So the end result should
  > look like
  >
  >         $(BUILD) -Werror -fstack-protector -Wstack-protector

Add -Wstack-protector.
Reported-by: NNamhyung Kim <namhyung@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Signed-off-by: NIngo Molnar <mingo@kernel.org>
Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

Namhyung Kim noticed that the volatile-register-var feature check
is superfluous:

 > The gcc manpage says this warning is enabled by -Wall, and we add -Wall
 > to CFLAGS before doing feature checks.  So all gcc versions that support
 > -Wvolatile-register-var enables it by default without this check and
 > older gcc versions will always fail the feature check.

Remove it - this will further speed up feature checks.
Reported-by: NNamhyung Kim <namhyung@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Signed-off-by: NIngo Molnar <mingo@kernel.org>
Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

Namhyung Kim reported these duplicate DPACKAGE definitions:

  test-libbfd:
       $(BUILD) -DPACKAGE='perf' -DPACKAGE=perf -lbfd -ldl

Fix all affected places and use Namhyung's suggestion that the
definition should look like a normal C string: -DPACKAGE='"perf"'.
Reported-by: NNamhyung Kim <namhyung@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Signed-off-by: NIngo Molnar <mingo@kernel.org>
Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

David Ahern reported that when passing in LDFLAGS=-static then
the feature checks still succeed - causing build failures down
the line because the static libraries are missing.

Solve this by passing through LDFLAGS to the feature-check
Makefile.
Reported-by: NDavid Ahern <dsahern@gmail.com>
Tested-by: NDavid Ahern <dsahern@gmail.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/20131007155129.GA1066@gmail.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Note that these are rarely executed tests, so we call feature_check() explicitly
and don't have them in CORE_FEATURE_CHECKS.

Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/n/tip-pvumlx6mbtfxffgrlwO2mRcx@git.kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

The detection of certain rarely detected features can be delayed
to when they are actually needed.

So speed up the common case of auto-detection by pre-building only
a core set of features and populating only their feature-flags.

[ Features not listed in CORE_FEATURES need to built explicitly
  via the feature_check() function. ]

(Also order the feature names alphabetically, while at it.)

Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/n/tip-xQkuveknd0gqla1dfxrqKpkl@git.kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

Concatenate all feature checks into test-all.c.

This can be built and checked faster than all the individual tests.

If test-all fails then we still check all the individual features, so
this is a pure speedup, it should have no effects on functionality.

Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/n/tip-5hlcb2qorzwfwrWTjiygjjih@git.kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

The strlcpy() feature check slows every build unnecessarily - so make it
a __weak function so it does not have to be auto-detected.

If the libc (or any other library) has an strlcpy() implementation it will
be used - otherwise our fallback is active.

Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/n/tip-zjbrcupapu08ePsyYhhhxiwk@git.kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/n/tip-ihnwe6cvglVkudyvcavP1wql@git.kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/n/tip-gmywXandzfxnlcbzlX6bkpw1@git.kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/n/tip-ektO8cgvupthhyqqczSok2sr@git.kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/n/tip-cdxdfv7Corpfvjg9Skezhvjn@git.kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/n/tip-raHmlqlnv0zexsrPau8hhane@git.kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/n/tip-9wfutfb8ufFHrddrwlejqrai@git.kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/n/tip-ggucqbwFwpxyuxde6dm7itHq@git.kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/n/tip-oumjyVjonjvgH8ts4mftagel@git.kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/n/tip-gfwzurn7wywiviLp7Swyyqsy@git.kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/n/tip-FGmpkydfwqlkaw7yy8ewjpza@git.kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/n/tip-orhejqtjao3vf4wxwBUdzhaz@git.kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/n/tip-vTiatsVyva3tfgh3vhxaidxl@git.kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/n/tip-wa9qstb8erbjreLxiHepzjfw@git.kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/n/tip-9fxnxjcmrgbSvipxlwsdQ8fg@git.kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/n/tip-dsx0fn9mjwfprizboANvtuup@git.kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/n/tip-nqnnsptw7ivOzhzbNjiun7ds@git.kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/n/tip-qznhihaasbysfqO7ffvRsf9q@git.kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/n/tip-xjfVewprrfhlo2wuzbnpVb1k@git.kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/n/tip-wicrcLCy2wkalka7iwsuzgpb@git.kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/n/tip-5dOevlybbwvbk3zTbcxrrqet@git.kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/n/tip-eyLYjhskzn6qxkoyjtjic4ap@git.kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/n/tip-gupddm9clctVYws3lyexfdhg@git.kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/n/tip-vixsrpggxFjhz7kppqgrGr6s@git.kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

Use GCC's -MD feature to generate a dependency file for each feature test .c file,
and include that .d file in the config/feature-checks/Makefile.

This allows us to do two things:

 - speed up feature tests
 - detect removal or changes in build dependencies - including system libraries/headers

Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/n/tip-Jfma8pmPnnqzpxjbs3hpgmsj@git.kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

Start the split-out of the feature check code by adding a list of features to be
tested, and rules to process that list by building its matching feature-check
file in config/feature-checks/test-<feature>.c.

Add 'hello' as the initial feature.

This structure will allow us to build split-out feature checks in parallel and
thus speed up feature detection dramatically.

No change in functionality: no feature check is used by the build rules yet.

Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/n/tip-pixkihgscFaohfFigq5yt9gs@git.kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>