Merge branch 'feat/su_accept_gid_args' of https://github.com/cgoesche/util-linux...

* 'feat/su_accept_gid_args' of https://github.com/cgoesche/util-linux-fork:
  unshare: use MAX_OF_UINT_TYPE instead of (type)-1
  chfn: enable the use of the username or UID
  unshare: use the new ul_get{grp,userpw}_str() routines
  login: use new xgetuserpw() instead of xgetpwnam()
  chsh: use new xgetuserpw() instead of xgetpwnam()
  su: accept group name and GID in -g and -G options
  tests: (su) test GID argument in --group option
  lib: (pwdutils.c) new library routines to get a group/passwd struct by name or GID/UID
  include/c.h: add MAX_OF_UINT_TYPE macro to get max num of an uint type

diff --cc lib/Makemodule.am
Simple merge

diff --cc login-utils/login.c
Simple merge

diff --cc login-utils/su-common.c
Simple merge