sulogin: increase util-linux compatibility

Change to root's HOME. Set some envvars. Steal ctty if necessary and possible.

function                                             old     new   delta
sulogin_main                                         240     340    +100
setup_environment                                    225     233      +8
su_main                                              479     474      -5
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(add/remove: 0/0 grow/shrink: 2/1 up/down: 108/-5)            Total: 103 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
3 files changed