Merge branch 'fc/untracked-zsh-prompt' into maint

* fc/untracked-zsh-prompt:
  prompt: fix untracked files for zsh

Author: gitster

contrib/completion/git-prompt.sh

@@ -340,7 +340,7 @@ __git_ps1 ()
 			   [ "$(git config --bool bash.showUntrackedFiles)" != "false" ] &&
 			   [ -n "$(git ls-files --others --exclude-standard)" ]
 			then
-				u="%"
+				u="%${ZSH_VERSION+%}"
 			fi
 
 			if [ -n "${GIT_PS1_SHOWUPSTREAM-}" ]; then