On my Archlinux machine, perf faild to build like below:

    CC       scripts/perl/Perf-Trace-Util/Context.o
  In file included from /usr/lib/perl5/core/perl/CORE/perl.h:3905:0,
                   from Context.xs:23:
  /usr/lib/perl5/core/perl/CORE/inline.h: In function :
  /usr/lib/perl5/core/perl/CORE/cop.h:612:13: warning: declaration of 'av'
                                  shadows a previous local [-Werror-shadow]
             AV *av =3D GvAV(PL_defgv);
                 ^
  /usr/lib/perl5/core/perl/CORE/inline.h:526:5: note: in expansion of
                                  macro 'CX_POP_SAVEARRAY'
         CX_POP_SAVEARRAY(cx);
         ^~~~~~~~~~~~~~~~
  In file included from /usr/lib/perl5/core/perl/CORE/perl.h:5853:0,
                   from Context.xs:23:
  /usr/lib/perl5/core/perl/CORE/inline.h:518:9: note:
                                  shadowed declaration is here
         AV *av;
             ^~

What I did to fix is adding '-Wno-shadow' as the error message said it's
the cause of the failure.  Since it's from the perl (not perf) code
base, we don't have the control so I just wanted to ignore the warning
when compiling perl scripting code.

Committer note:

This also fixes the build on Fedora Rawhide.
Signed-off-by: NNamhyung Kim <namhyung@kernel.org>
Tested-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20160802024317.31725-1-namhyung@kernel.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

Move the scripts objects building under build framework to be included
in the libperf build object.
Signed-off-by: NJiri Olsa <jolsa@kernel.org>
Tested-by: NSukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Tested-by: NWill Deacon <will.deacon@arm.com>
Cc: Alexis Berlemont <alexis.berlemont@gmail.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-ry8pd41ahwpq9h46i8te33c7@git.kernel.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>