[PATCH v3 08/12] perf tests: Silence the libbfd probe in build-test

[Arnaldo Carvalho de Melo <acme@kernel.org>]

build-test evaluates the libbfd probe at parse time and the compiler's
stderr isn't captured by $(shell ...), so without binutils-devel it
prints "bfd.h: No such file or directory" once per tests/make
invocation, five times per run.

Redirect the compiler's stderr; the empty result still skips the
nondistro tests as intended.

Fixes: 523471c5163659c6 ("perf build: Skip nondistro build test if libbfd is old")
Cc: James Clark <james.clark@linaro.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/tests/make | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/perf/tests/make b/tools/perf/tests/make
index 7524de5228029e7e..e6d7ac49b5b1693d 100644
--- a/tools/perf/tests/make
+++ b/tools/perf/tests/make
@@ -128,7 +128,7 @@ make_minimal        += NO_SDT=1 NO_JVMTI=1 NO_LIBZSTD=1
 make_minimal        += NO_CAPSTONE=1
 
 # binutils 2_42 and newer have bfd_thread_init()
-new_libbfd := $(shell echo '#include <bfd.h>' | $(CC) -E -x c - | grep bfd_thread_init)
+new_libbfd := $(shell echo '#include <bfd.h>' | $(CC) -E -x c - 2>/dev/null | grep bfd_thread_init)
 
 # Whether libLLVM can be built, which needs the llvm-devel/llvm-dev headers and
 # libraries of version 13 or newer, not just llvm-config. This mirrors the
-- 
2.56.0