A public service announcement for those running Zsh on Mac OS X.

Upgrading to El Capitan (OS X 10.11) will install a /etc/zprofile that
contains

    # system-wide environment settings for zsh(1)
    if [ -x /usr/libexec/path_helper ]; then
       eval `/usr/libexec/path_helper -s`
    fi

On a new login shell that will be sourced after your $HOME/.zshenv. If you
set your $PATH in your .zshenv the /usr/libexec/path_helper program will
alter the order of the directories. The order appears random so it's
probably using a hashed set to avoid having the same directory appear more
than once in the result.

You can't remove /usr/libexec/path_helper due to the new security
mechanisms (at least not without booting from a recovery disk) but you can
remove /etc/zprofile which is what I did to keep my $PATH from being mucked
with.

-- 
Kurtis Rader
Caretaker of the exceptional canines Junior and Hank