[tip:perf/core] perf tools: Define _GNU_SOURCE on pthread_attr_setaffinity_np feature check

[tip-bot for Josh Boyer <tipbot@zytor.com>]

Commit-ID:  39f5704399042fff5f0d5f6af32bbbc3e787a897
Gitweb:     http://git.kernel.org/tip/39f5704399042fff5f0d5f6af32bbbc3e787a897
Author:     Josh Boyer <jwboyer@fedoraproject.org>
AuthorDate: Wed, 11 Feb 2015 11:24:05 -0500
Committer:  Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Wed, 11 Feb 2015 17:38:55 -0300

perf tools: Define _GNU_SOURCE on pthread_attr_setaffinity_np feature check

The man page for pthread_attr_set_affinity_np states that _GNU_SOURCE
must be defined before pthread.h is included in order to get the proper
function declaration.  Define this in the Makefile.

Without this defined, the feature check fails on a Fedora system with
gcc5 and then the perf build later fails with conflicting prototypes for
the function.

Signed-off-by: Josh Boyer <jwboyer@fedoraproject.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Vineet Gupta <Vineet.Gupta1@synopsys.com>
Link: http://lkml.kernel.org/r/20150211162404.GA15522@hansolo.redhat.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/config/feature-checks/Makefile | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/perf/config/feature-checks/Makefile b/tools/perf/config/feature-checks/Makefile
index 42ac05a..b32ff33 100644
--- a/tools/perf/config/feature-checks/Makefile
+++ b/tools/perf/config/feature-checks/Makefile
@@ -49,7 +49,7 @@ test-hello.bin:
 	$(BUILD)
 
 test-pthread-attr-setaffinity-np.bin:
-	$(BUILD) -Werror -lpthread
+	$(BUILD) -D_GNU_SOURCE -Werror -lpthread
 
 test-stackprotector-all.bin:
 	$(BUILD) -Werror -fstack-protector-all