Implement libzstd feature check, NO_LIBZSTD and LIBZSTD_DIR defines to
override Zstd library sources or disable the feature from the command
line:

  $ make -C tools/perf LIBZSTD_DIR=/path/to/zstd/sources/ clean all
  $ make -C tools/perf NO_LIBZSTD=1 clean all

Auto detection feature status is reported just before compilation
starts.  If your system has some version of the zstd library
preinstalled then the build system finds and uses it during the build.

If you still prefer to compile with some other version of zstd library
you have capability to refer the compilation to that version using
LIBZSTD_DIR define.
Signed-off-by: Alexey Budankov <alexey.budankov@linux.intel.com>
Reviewed-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/9b4cd8b0-10a3-1f1e-8d6b-5922a7ca216b@linux.intel.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>