perf python: Remove -fstack-protector-strong if clang doesn't have it

perf python: Remove -fstack-protector-strong if clang doesn't have it

Some distros put -fstack-protector-strong in the compiler flags to be
used to build python extensions, but then, the clang version in that
distro doesn't know about that, only gcc does.

Check if that is the case and remove it from the set of options used to
build the python binding with clang.

Case at hand:

oraclelinux:7

  $ head -2 /etc/os-release
  NAME="Oracle Linux Server"
  VERSION="7.6"
  $ grep stack-protector /usr/lib64/python2.7/_sysconfigdata.py | head -1 | cut -c-120
 'CFLAGS': '-fno-strict-aliasing -O2 -g -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector-strong --para
  $
  gcc version 4.8.5 20150623 (Red Hat 4.8.5-36.0.1) (GCC)
  clang version 3.4.2 (tags/RELEASE_34/dot2-final)

  clang: error: unknown argument: '-fstack-protector-strong'
  clang: error: unknown argument: '-fstack-protector-strong'
  error: command 'clang' failed with exit status 1
  cp: cannot stat '/tmp/build/perf/python_ext_build/lib/perf*.so': No such file or directory
  make[2]: *** [/tmp/build/perf/python/perf.so] Error 1

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-brmp2415zxpbhz45etkgjoma@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>