Patch from Tito to fix memory leak upon error.

libbb/xreadlink.c

@@ -25,6 +25,7 @@ extern char *xreadlink(const char *path)
 		readsize = readlink(path, buf, bufsize); /* 1st try */
 		if (readsize == -1) {
 			bb_perror_msg("%s", path);
+			free(buf);
 			return NULL;
 		}
 	}