use xcalloc() to allocate zero-initialized memory

Use xcalloc() instead of xmalloc() followed by memset() to allocate
and zero out memory because it's shorter and avoids duplicating the
function parameters.

Signed-off-by: Rene Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/clean.c

@@ -621,8 +621,7 @@ static int *list_and_choose(struct menu_opts *opts, struct menu_stuff *stuff)
 				nr += chosen[i];
 		}
 
-		result = xmalloc(sizeof(int) * (nr + 1));
+		result = xcalloc(nr + 1, sizeof(int));
-		memset(result, 0, sizeof(int) * (nr + 1));
 		for (i = 0; i < stuff->nr && j < nr; i++) {
 			if (chosen[i])
 				result[j++] = i;

builtin/index-pack.c

@@ -362,8 +362,7 @@ static void set_thread_data(struct thread_local *data)
 
 static struct base_data *alloc_base_data(void)
 {
-	struct base_data *base = xmalloc(sizeof(struct base_data));
+	struct base_data *base = xcalloc(1, sizeof(struct base_data));
-	memset(base, 0, sizeof(*base));
 	base->ref_last = -1;
 	base->ofs_last = -1;
 	return base;

compat/mingw.c

@@ -1226,8 +1226,7 @@ static int WSAAPI getaddrinfo_stub(const char *node, const char *service,
 	else
 		ai->ai_canonname = NULL;
 
-	sin = xmalloc(ai->ai_addrlen);
+	sin = xcalloc(1, ai->ai_addrlen);
-	memset(sin, 0, ai->ai_addrlen);
 	sin->sin_family = AF_INET;
 	/* Note: getaddrinfo is supposed to allow service to be a string,
 	 * which should be looked up using getservbyname. This is

pathspec.c

@@ -389,8 +389,7 @@ void parse_pathspec(struct pathspec *pathspec,
 		if (!(flags & PATHSPEC_PREFER_CWD))
 			die("BUG: PATHSPEC_PREFER_CWD requires arguments");
 
-		pathspec->items = item = xmalloc(sizeof(*item));
+		pathspec->items = item = xcalloc(1, sizeof(*item));
-		memset(item, 0, sizeof(*item));
 		item->match = prefix;
 		item->original = prefix;
 		item->nowildcard_len = item->len = strlen(prefix);