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>

tools/perf/util/util.h

@@ -302,6 +302,11 @@ extern int xdup(int fd);
 extern FILE *xfdopen(int fd, const char *mode);
 extern int xmkstemp(char *template);
 
+static inline void *zalloc(size_t size)
+{
+	return calloc(1, size);
+}
+
 static inline size_t xsize_t(off_t len)
 {
 	return (size_t)len;