[tip:perf/core] perf jvmti: Fix linker error when libelf config is disabled

[tip-bot for Sudeep Holla]

Commit-ID:  5d90faf45427dd76fadbe7a4dc4fce3b6f87b550
Gitweb:     http://git.kernel.org/tip/5d90faf45427dd76fadbe7a4dc4fce3b6f87b550
Author:     Sudeep Holla <Sudeep.Holla@xxxxxxx>
AuthorDate: Tue, 18 Jul 2017 18:18:39 -0700
Committer:  Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
CommitDate: Tue, 25 Jul 2017 11:23:53 -0300

perf jvmti: Fix linker error when libelf config is disabled

When libelf is disabled in the configuration, we get the following
linker error:

  LINK     libperf-jvmti.so
  ld: cannot find -lelf
  Makefile.perf:515: recipe for target 'libperf-jvmti.so' failed

Jiri pointed out that both librt and libelf are not really required. So
this patch fixes the linker error by getting rid of unwanted libraries
in the linker stage.

Signed-off-by: Sudeep Holla <sudeep.holla@xxxxxxx>
Acked-by: David Carrillo-Cisneros <davidcc@xxxxxxxxxx>
Acked-by: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
Cc: Elena Reshetova <elena.reshetova@xxxxxxxxx>
Cc: Kees Kook <keescook@xxxxxxxxxxxx>
Cc: Paul Turner <pjt@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Stephane Eranian <eranian@xxxxxxxxxx>
Cc: Sudeep Holla <sudeep.holla@xxxxxxx>
Cc: Wang Nan <wangnan0@xxxxxxxxxx>
Fixes: 209045adc2bb ("perf tools: add JVMTI agent library")
Link: http://lkml.kernel.org/r/20170719011839.99399-5-davidcc@xxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
 tools/perf/Makefile.perf | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/perf/Makefile.perf b/tools/perf/Makefile.perf
index 100a6c1..d66f90e 100644
--- a/tools/perf/Makefile.perf
+++ b/tools/perf/Makefile.perf
@@ -518,7 +518,7 @@ $(LIBJVMTI_IN): FORCE
 	$(Q)$(MAKE) -f $(srctree)/tools/build/Makefile.build dir=jvmti obj=jvmti
 
 $(OUTPUT)$(LIBJVMTI): $(LIBJVMTI_IN)
-	$(QUIET_LINK)$(CC) -shared -Wl,-soname -Wl,$(LIBJVMTI) -o $@ $< -lelf -lrt
+	$(QUIET_LINK)$(CC) -shared -Wl,-soname -Wl,$(LIBJVMTI) -o $@ $<
 endif
 
 $(patsubst perf-%,%.o,$(PROGRAMS)): $(wildcard */*.h)