Move broken OS X /etc/zshenv detection to post-up hook

This is so it doesn't run every time when zsh starts in interactive
mode, but just once per `rcup`.

hooks/post-up

@@ -1,4 +1,4 @@
-#!/bin/sh
+#!/bin/bash
 
 touch $HOME/.psqlrc.local
 
@@ -7,3 +7,28 @@ if [ ! -e $HOME/.vim/autoload/plug.vim ]; then
       https://raw.githubusercontent.com/junegunn/vim-plug/master/plug.vim
 fi
 vim -u $HOME/.vimrc.bundles +PlugInstall +PlugClean! +qa
+
+# detect old OS X broken /etc/zshenv and suggest rename
+if grep -qw path_helper /etc/zshenv 2>/dev/null; then
+  fg_red=$'\e[31m'
+  fg_bold_white=$'\e[1;37m'
+  reset_color=$'\e[m'
+
+  # resolve BASH_SOURCE to absolute path
+  bash_source="$BASH_SOURCE"
+  if [[ $bash_source == */* ]]; then
+    pushd "${bash_source%/*}" >/dev/null
+    bash_source="${PWD}/${bash_source##*/}"
+    popd >/dev/null
+  fi
+
+  cat <<MSG >&2
+${fg_red}Warning:${reset_color} \`/etc/zshenv' configuration file on your system may cause unexpected
+PATH changes on subsequent invocations of the zsh shell. The solution is to
+rename the file to \`zprofile':
+  ${fg_bold_white}sudo mv /etc/{zshenv,zprofile}${reset_color}
+
+(called from ${bash_source}:${LINENO})
+
+MSG
+fi

zshrc

@@ -111,18 +111,5 @@ _load_settings() {
 }
 _load_settings "$HOME/.zsh/configs"
 
-# detect old OS X broken /etc/zshenv and suggest rename
-if grep -qw path_helper /etc/zshenv 2>/dev/null; then
-  cat <<MSG >&2
-${fg[red]}Warning:${reset_color} \`/etc/zshenv' configuration file on your system may cause unexpected
-PATH changes on subsequent invocations of the zsh shell. The solution is to
-rename the file to \`zprofile':
-  ${fg_bold[white]}sudo mv /etc/{zshenv,zprofile}${reset_color}
-
-(called from ${(%):-%N:%i})
-
-MSG
-fi
-
 # Local config
 [[ -f ~/.zshrc.local ]] && source ~/.zshrc.local