[PATCH] perf: Fix parallel build

[Eric Sandeen <sandeen@redhat.com>]

Parallel builds of perf were failing for me on a 32p box, with:

    * new build flags or prefix
util/pmu.l:7:23: error: pmu-bison.h: No such file or directory

...

make: *** [util/pmu-flex.o] Error 1
make: *** Waiting for unfinished jobs....

This can pretty quickly be seen by adding a sleep in front of
the bison call in tools/perf/Makefile and running make -j4 on a
smaller box:

	sleep 10; $(QUIET_BISON)$(BISON) -v util/pmu.y -d -o $(OUTPUT)util/pmu-bison.c

Adding the following dependency fixes it for me:

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
---

diff --git a/tools/perf/Makefile b/tools/perf/Makefile
index bad726a..6c389d9 100644
--- a/tools/perf/Makefile
+++ b/tools/perf/Makefile
@@ -219,7 +219,7 @@ $(OUTPUT)util/parse-events-flex.c: util/parse-events.l
 $(OUTPUT)util/parse-events-bison.c: util/parse-events.y
 	$(QUIET_BISON)$(BISON) -v util/parse-events.y -d $(PARSER_DEBUG_BISON) -o $(OUTPUT)util/parse-events-bison.c
 
-$(OUTPUT)util/pmu-flex.c: util/pmu.l
+$(OUTPUT)util/pmu-flex.c: util/pmu.l util/pmu-bison.c
 	$(QUIET_FLEX)$(FLEX) --header-file=$(OUTPUT)util/pmu-flex.h -t util/pmu.l > $(OUTPUT)util/pmu-flex.c
 
 $(OUTPUT)util/pmu-bison.c: util/pmu.y