Warn people who might have PATH and similar configuration in their
`~/.zshenv.local` that they should upgrade to `~/.zshrc.local` since
that's a much better phase for such configuration. This is for backwards
compatibility with people's personal configurations from pre-El Capitan
days.
The generic `.zshenv` file from zsh distribution[1] advises:
> .zshenv is sourced on ALL invocations of the shell, unless the -f
> option is set. It should NOT normally contain commands to set the
> command search path, or other common environment variables unless you
> really know what you're doing. E.g. running `PATH=/custom/path gdb program`
> sources this file (when gdb runs the program via $SHELL), so you want
> to be sure not to override a custom environment in such cases. Note
> also that .zshenv should not contain commands that produce output or
> assume the shell is attached to a tty.
[1]: http://sourceforge.net/p/zsh/code/ci/master/tree/StartupFiles/zshenv
Making tweaks such as setting EDITOR or changing PATH only makes sense
for interactive shells, e.g. those that open in your Terminal window or
when you log in to a server. Non-interactive shells (such as those
started by running `zsh myscript.zsh` or any executable with `zsh`
shebang) should instead inherit those values from the environment.
Furthermore, changing PATH in `~/.zshenv` is not advised since stock
OS X `/etc/zprofile` will reoder PATH by means of `path_helper`, so it's
better to make any additional PATH manipulation in `~/.zprofile` or
`~/.zshrc`.
* Adding /usr/local/bin to path in `~/.zshenv` causes it to be in my path twice one right after the other. /usr/local/bin is already added to the path in the correct order on OSX Yosemite by the /etc/paths file.
* Remove /usr/local/bin from path export in zshenv
From the [Zsh manual](http://zsh.sourceforge.net/Intro/intro_3.html):
> '.zshenv' is sourced on all invocations of the shell, unless the -f option is
> set. It should contain commands to set the command search path, plus other
> important environment variables. `.zshenv' should not contain commands that
> produce output or assume the shell is attached to a tty.
Why is this important? [Alfred](http://www.alfredapp.com/) workflows run in
non-interactive shells. When the `$PATH` is set, or `rbenv` is initialized, in
`zshrc` instead of `zshenv`, those workflows will not use the correct Ruby
version and might not have access to certain bin files, such as those from
`$HOME/.bin/` or Homebrew.
