[fzf-tmux] Use fzf border instead of tmux popup border (#2908)

Co-authored-by: Yang Tian <yang.tian@getcruise.com>
Co-authored-by: Junegunn Choi <junegunn.c@gmail.com>

CHANGELOG.md

@@ -4,6 +4,13 @@ CHANGELOG
 0.32.1
 ------
 - Fixed incorrect ordering of `--tiebreak=chunk`
+- fzf-tmux will show fzf border instead of tmux popup border (requires tmux 3.3)
+  ```sh
+  fzf-tmux -p70%
+  fzf-tmux -p70% --color=border:bright-red
+  fzf-tmux -p100%,60% --color=border:bright-yellow --border=horizontal
+  fzf-tmux -p70%,100% --color=border:bright-green --border=vertical
+  ```
 
 0.32.0
 ------

bin/fzf-tmux

@@ -181,7 +181,14 @@ trap 'cleanup 1' SIGUSR1
 trap 'cleanup' EXIT
 
 envs="export TERM=$TERM "
-[[ "$opt" =~ "-E" ]] && FZF_DEFAULT_OPTS="--margin 0,1 $FZF_DEFAULT_OPTS"
+if [[ "$opt" =~ "-E" ]]; then
+  FZF_DEFAULT_OPTS="--margin 0,1 $FZF_DEFAULT_OPTS"
+  tmux_verson=$(tmux -V)
+  if [[ ! $tmux_verson =~ 3\.2 ]]; then
+    FZF_DEFAULT_OPTS="--border $FZF_DEFAULT_OPTS"
+    opt="-B $opt"
+  fi
+fi
 [[ -n "$FZF_DEFAULT_OPTS"    ]] && envs="$envs FZF_DEFAULT_OPTS=$(printf %q "$FZF_DEFAULT_OPTS")"
 [[ -n "$FZF_DEFAULT_COMMAND" ]] && envs="$envs FZF_DEFAULT_COMMAND=$(printf %q "$FZF_DEFAULT_COMMAND")"
 echo "$envs;" > "$argsf"