perf tools: Introduce zalloc() for the common calloc(1, N) case

This way we type less characters and it looks more like the
kzalloc kernel counterpart.

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frédéric Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <1259071517-3242-3-git-send-email-acme@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/tools/perf/util/thread.c b/tools/perf/util/thread.c
index 0f6d78c..1796625 100644
--- a/tools/perf/util/thread.c
+++ b/tools/perf/util/thread.c
@@ -11,7 +11,7 @@
 
 static struct thread *thread__new(pid_t pid)
 {
-	struct thread *self = calloc(1, sizeof(*self));
+	struct thread *self = zalloc(sizeof(*self));
 
 	if (self != NULL) {
 		self->pid = pid;