[tip:perf/core] perf tools: Use shell function for perl cflags retrieval

[tip-bot for Jiri Olsa]

Commit-ID:  86f5fe01cf3ad42e99e7655dec93e0e36ef65614
Gitweb:     https://git.kernel.org/tip/86f5fe01cf3ad42e99e7655dec93e0e36ef65614
Author:     Jiri Olsa <jolsa@xxxxxxxxxx>
AuthorDate: Wed, 8 Nov 2017 11:27:37 +0100
Committer:  Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
CommitDate: Thu, 16 Nov 2017 14:49:52 -0300

perf tools: Use shell function for perl cflags retrieval

Using the shell function for perl CFLAGS retrieval instead of back
quotes (``). Both execute shell with the command, but the latter is more
explicit and seems to be the preferred way.

Also we don't have any other use of the back quotes in perf Makefiles.

Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: David Ahern <dsahern@xxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/20171108102739.30338-2-jolsa@xxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
 tools/perf/Makefile.config | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/perf/Makefile.config b/tools/perf/Makefile.config
index 63f534a..f6786fa 100644
--- a/tools/perf/Makefile.config
+++ b/tools/perf/Makefile.config
@@ -579,7 +579,7 @@ else
   PERL_EMBED_LDOPTS = $(shell perl -MExtUtils::Embed -e ldopts 2>/dev/null)
   PERL_EMBED_LDFLAGS = $(call strip-libs,$(PERL_EMBED_LDOPTS))
   PERL_EMBED_LIBADD = $(call grep-libs,$(PERL_EMBED_LDOPTS))
-  PERL_EMBED_CCOPTS = `perl -MExtUtils::Embed -e ccopts 2>/dev/null`
+  PERL_EMBED_CCOPTS = $(shell perl -MExtUtils::Embed -e ccopts 2>/dev/null)
   FLAGS_PERL_EMBED=$(PERL_EMBED_CCOPTS) $(PERL_EMBED_LDOPTS)
 
   ifneq ($(feature-libperl), 1)