tools build: Add test for presence of __get_cpuid() gcc builtin

The auxtrace code needed by Intel PT uses the __get_cpuid() gcc builtin,
that is not present in old systems, breaking the build.

Add a test to check for that builtin and disable AUXTRACE in those
systems.

[acme@rhel5 linux]$ make NO_LIBPERL=1 -C tools/perf O=/tmp/build/perf install-bin
make: Entering directory `/home/acme/git/linux/tools/perf'
BUILD: Doing 'make -j2' parallel build

Auto-detecting system features:
<SNIP>
... lzma: [ on ]
... get_cpuid: [ OFF ]
<SNIP>
config/Makefile:630: Your gcc lacks the __get_cpuid() builtin, disables support for auxtrace/Intel PT, please install a newer gcc
MKDIR /tmp/build/perf/util/
<SNIP>

This fixes the build on old systems such as RHEL/CentOS 5.11.

Cc: Adrian Hunter <[e-mail]>
Cc: Borislav Petkov <[e-mail]>
Cc: David Ahern <[e-mail]>
Cc: Frederic Weisbecker <[e-mail]>
Cc: Jiri Olsa <[e-mail]>
Cc: Namhyung Kim <[e-mail]>
Cc: "Naveen N. Rao" <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Cc: Srikar Dronamraju <[e-mail]>
Cc: Stephane Eranian <[e-mail]>
Cc: Victor Kamensky <[e-mail]>
Cc: Vinson Lee <[e-mail]>
Cc: Wang Nan <[e-mail]>
Link: http://lkml.kernel.org/n/[e-mail]
Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>

tools/build/Makefile.feature

···
 	timerfd				\
 	libdw-dwarf-unwind		\
 	zlib				\
-	lzma
+	lzma				\
+	get_cpuid
 
 FEATURE_DISPLAY ?=			\
 	dwarf				\
···
 	libunwind			\
 	libdw-dwarf-unwind		\
 	zlib				\
-	lzma
+	lzma				\
+	get_cpuid
 
 # Set FEATURE_CHECK_(C|LD)FLAGS-all for all FEATURE_TESTS features.
 # If in the future we need per-feature checks/flags for features not

tools/build/feature/Makefile

···
 	test-compile-x32.bin		\
 	test-zlib.bin			\
 	test-lzma.bin			\
-	test-bpf.bin
+	test-bpf.bin			\
+	test-get_cpuid.bin
 
 CC := $(CROSS_COMPILE)gcc -MD
 PKG_CONFIG := $(CROSS_COMPILE)pkg-config
···
 
 test-lzma.bin:
 	$(BUILD) -llzma
+
+test-get_cpuid.bin:
+	$(BUILD)
 
 test-bpf.bin:
 	$(BUILD)

tools/build/feature/test-all.c

···
 # include "test-lzma.c"
 #undef main
 
+#define main main_test_get_cpuid
+# include "test-get_cpuid.c"
+#undef main
+
 int main(int argc, char *argv[])
 {
 	main_test_libpython();
···
 	main_test_zlib();
 	main_test_pthread_attr_setaffinity_np();
 	main_test_lzma();
+	main_test_get_cpuid();
 
 	return 0;
 }

tools/build/feature/test-get_cpuid.c

···
+#include <cpuid.h>
+
+int main(void)
+{
+	unsigned int eax = 0, ebx = 0, ecx = 0, edx = 0;
+	return __get_cpuid(0x15, &eax, &ebx, &ecx, &edx);
+}

tools/perf/config/Makefile

···
 endif
 
 ifndef NO_AUXTRACE
-  $(call detected,CONFIG_AUXTRACE)
-  CFLAGS += -DHAVE_AUXTRACE_SUPPORT
+  ifeq ($(feature-get_cpuid), 0)
+    msg := $(warning Your gcc lacks the __get_cpuid() builtin, disables support for auxtrace/Intel PT, please install a newer gcc);
+    NO_AUXTRACE := 1
+  else
+    $(call detected,CONFIG_AUXTRACE)
+    CFLAGS += -DHAVE_AUXTRACE_SUPPORT
+  endif
 endif
 
 # Among the variables below, these: