termsupport: protect title() with `emulate -L zsh`
This prevents it from malfunctioning when `setopt prompt_subst` is off.
Diff
1diff --git a/lib/termsupport.zsh b/lib/termsupport.zsh
2index e1c2e2f93a3b376a02180d21cdddf01f0bcdcb29..973c4dcf6dd0426ceada3018d81c54667d456787 100644
3--- a/lib/termsupport.zsh
4+++ b/lib/termsupport.zsh
5@@ -7,6 +7,9 @@
6 # (In screen, only short_tab_title is used)
7 # Limited support for Apple Terminal (Terminal can't set window and tab separately)
8 function title {
9+ emulate -L zsh
10+ setopt prompt_subst
11+
12 [[ "$EMACS" == *term* ]] && return
1314 # if $2 is unset use $1 as default