Pull up following revision(s) (requested by kamil in ticket #901):

lib/libutil/pty.c: revision 1.32

Fix stack use after scope in libutil/pty

The pt variable's elements are used after the end of the pt scope.

A move of pt to outer scope fixes this.

Detected with MKSANITIZER/ASan with tmux(1), a forkpty(3) user.

(martin)