Remove xcalloc() and convert its callers to xzalloc(). About half of them

were using "1" as one of the arguments anyway, and as for the rest a multiply
and a push isn't noticeably bigger than pushing two arguments on the stack.

coreutils/sort.c

@@ -120,7 +120,7 @@ static struct sort_key *add_key(void)
 {
 	struct sort_key **pkey=&key_list;
 	while(*pkey) pkey=&((*pkey)->next_key);
-	return *pkey=xcalloc(1,sizeof(struct sort_key));
+	return *pkey = xzalloc(sizeof(struct sort_key));
 }
 
 #define GET_LINE(fp) (global_flags&FLAG_z) ? bb_get_chunk_from_file(fp,NULL) \