Comment # 5 on bug 907041 from Guido Berh�rster

I don't really like this, it's even more deviating from upstream behavior and
somewhat unexpected for people like me who set TMPDIR and expect tmux to obey
that.

@Marcus:
So you have TMPDIR set to /tmp but only for the shell you start in a terminal
emulator, and if so why since /tmp should the default anyway? Note that this is
documented and expected behavior in tmux and only worked previously by
coincidence because TMPDIR and the fallback /tmp were the same.