tools build: Add test for presence of numa_num_possible_cpus() in libnuma

The existing numa test checks only if numa.h and numa_available() are
present, but that can be satisfied with an old libnuma that is not
enough for the 'perf bench numa' entry, so add a test to check for that:

[acme@rhel5 linux]$ make NO_AUXTRACE=1 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:
... libelf: [ on ]
... libnuma: [ on ]
... numa_num_possible_cpus: [ OFF ]
... libperl: [ on ]

<SNIP>
config/Makefile:577: Old numa library found, disables 'perf bench numa mem' benchmark, please install numactl-devel/libnuma-devel/libnuma-dev >= 2.0.8
INSTALL binaries
<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

···
 	libelf-getphdrnum		\
 	libelf-mmap			\
 	libnuma				\
+	numa_num_possible_cpus		\
 	libperl				\
 	libpython			\
 	libpython-version		\
···
 	libbfd				\
 	libelf				\
 	libnuma				\
+	numa_num_possible_cpus		\
 	libperl				\
 	libpython			\
 	libslang			\

tools/build/feature/Makefile

···
 	test-libelf-getphdrnum.bin	\
 	test-libelf-mmap.bin		\
 	test-libnuma.bin		\
+	test-numa_num_possible_cpus.bin	\
 	test-libperl.bin		\
 	test-libpython.bin		\
 	test-libpython-version.bin	\
···
 	$(BUILD) -lelf
 
 test-libnuma.bin:
+	$(BUILD) -lnuma
+
+test-numa_num_possible_cpus.bin:
 	$(BUILD) -lnuma
 
 test-libunwind.bin:

tools/build/feature/test-all.c

···
 # include "test-libnuma.c"
 #undef main
 
+#define main main_test_numa_num_possible_cpus
+# include "test-numa_num_possible_cpus.c"
+#undef main
+
 #define main main_test_timerfd
 # include "test-timerfd.c"
 #undef main
···
 	main_test_libbfd();
 	main_test_backtrace();
 	main_test_libnuma();
+	main_test_numa_num_possible_cpus();
 	main_test_timerfd();
 	main_test_stackprotector_all();
 	main_test_libdw_dwarf_unwind();

tools/build/feature/test-numa_num_possible_cpus.c

···
+#include <numa.h>
+
+int main(void)
+{
+	return numa_num_possible_cpus();
+}

tools/perf/config/Makefile

···
     msg := $(warning No numa.h found, disables 'perf bench numa mem' benchmark, please install numactl-devel/libnuma-devel/libnuma-dev);
     NO_LIBNUMA := 1
   else
-    CFLAGS += -DHAVE_LIBNUMA_SUPPORT
-    EXTLIBS += -lnuma
-    $(call detected,CONFIG_NUMA)
+    ifeq ($(feature-numa_num_possible_cpus), 0)
+      msg := $(warning Old numa library found, disables 'perf bench numa mem' benchmark, please install numactl-devel/libnuma-devel/libnuma-dev >= 2.0.8);
+      NO_LIBNUMA := 1
+    else
+      CFLAGS += -DHAVE_LIBNUMA_SUPPORT
+      EXTLIBS += -lnuma
+      $(call detected,CONFIG_NUMA)
+    endif
   endif
 endif