perf trace: Don't supress zeroed args when there is an strarray entry for it

Case in hand:

   9.682 ( 0.001 ms): Xorg/13079 setitimer(which: REAL, value: 0x7fffede42470) = 0

ITIMER_REAL is zero.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-6hnoqsjh99t4hxi3xu2nlwep@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/builtin-trace.c

@@ -940,8 +940,15 @@ static size_t syscall__scnprintf_args(struct syscall *sc, char *bf, size_t size,
 		     field = field->next, ++arg.idx, bit <<= 1) {
 			if (arg.mask & bit)
 				continue;
-
-			if (args[arg.idx] == 0)
+			/*
+ 			 * Suppress this argument if its value is zero and
+ 			 * and we don't have a string associated in an
+ 			 * strarray for it.
+ 			 */
+			if (args[arg.idx] == 0 &&
+			    !(sc->arg_scnprintf &&
+			      sc->arg_scnprintf[arg.idx] == SCA_STRARRAY &&
+			      sc->arg_parm[arg.idx]))
 				continue;
 
 			printed += scnprintf(bf + printed, size - printed,