perf build: Add sdt feature detection

This checks whether sys/sdt.h is available or not, which is required for
DTRACE_PROBE().

We can disable this feature by passing NO_SDT=1 when building.

This flag will be used for SDT test case and further SDT events in
perftools.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com>
Cc: Brendan Gregg <brendan.d.gregg@gmail.com>
Cc: Hemant Kumar <hemant@linux.vnet.ibm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/146831795615.17065.17513820540591053933.stgit@devbox
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/build/feature/Makefile

@@ -45,7 +45,8 @@ FILES=					\
 	test-zlib.bin			\
 	test-lzma.bin			\
 	test-bpf.bin			\
-	test-get_cpuid.bin
+	test-get_cpuid.bin		\
+	test-sdt.bin
 
 FILES := $(addprefix $(OUTPUT),$(FILES))
 
@@ -213,6 +214,9 @@ $(OUTPUT)test-get_cpuid.bin:
 $(OUTPUT)test-bpf.bin:
 	$(BUILD)
 
+$(OUTPUT)test-sdt.bin:
+	$(BUILD)
+
 -include $(OUTPUT)*.d
 
 ###############################

tools/build/feature/test-all.c

@@ -145,6 +145,10 @@
 # include "test-libcrypto.c"
 #undef main
 
+#define main main_test_sdt
+# include "test-sdt.c"
+#undef main
+
 int main(int argc, char *argv[])
 {
 	main_test_libpython();
@@ -178,6 +182,7 @@ int main(int argc, char *argv[])
 	main_test_get_cpuid();
 	main_test_bpf();
 	main_test_libcrypto();
+	main_test_sdt();
 
 	return 0;
 }

tools/build/feature/test-sdt.c

@@ -0,0 +1,7 @@
+#include <sys/sdt.h>
+
+int main(void)
+{
+	DTRACE_PROBE(provider, name);
+	return 0;
+}