which: rewrite

function                                             old     new   delta
which_main                                           237     212     -25

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
trylink: emit names of linked executables

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
Merge branch 'master' of git+ssh://vda@busybox.net/var/lib/git/busybox
getty: explain when setsid() fails. no code changes

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