Use memtoll() when parsing the backlog-size option.

src/config.c

@@ -256,7 +256,7 @@ void loadServerConfigFromString(char *config) {
                 err = "argument must be 'yes' or 'no'"; goto loaderr;
             }
         } else if (!strcasecmp(argv[0],"repl-backlog-size") && argc == 2) {
-            long long size = strtoll(argv[1],NULL,10);
+            long long size = memtoll(argv[1],NULL);
             if (size <= 0) {
                 err = "repl-backlog-size must be 1 or greater.";
                 goto loaderr;