Prerequisite: X11 must be installed and started when you want to use your editor.
Then, you need to have the DISPLAY environment variable defined at the begining of your mac session. For this, create or modify the file: ~/.MacOSX/environment.plist, where ~ is your start folder. You will probaby have to begin with creating the folder .MacOSX.
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple Computer//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">