glob: fix bugs with long login names Problem reported by Adhemerval Zanella in: https://sourceware.org/ml/libc-alpha/2017-08/msg00455.html * lib/glob.c (GET_LOGIN_NAME_MAX): Remove. (glob): Use the same scratch buffer for both getlogin_r and getpwnam_r. Don’t require preallocation of the login name. This simplifies storage allocation, and corrects the handling of long login names.