perf build: Move feature checks code under tools/build

Moving feature checks code under tools/build directory.

Changing also $feature_dir to point to new feature directory location
and perf Makefiles to include Makefile.feature from new location.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: David Ahern <david.ahern@oracle.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/n/tip-3lamtb30dhf4wo99y1n8kxg0@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/build/feature/test-timerfd.c

@@ -0,0 +1,18 @@
+/*
+ * test for timerfd functions used by perf-kvm-stat-live
+ */
+#include <sys/timerfd.h>
+
+int main(void)
+{
+	struct itimerspec new_value;
+
+	int fd = timerfd_create(CLOCK_MONOTONIC, TFD_NONBLOCK);
+	if (fd < 0)
+		return 1;
+
+	if (timerfd_settime(fd, 0, &new_value, NULL) != 0)
+		return 1;
+
+	return 0;
+}