Identify development vs. production server in PHP

Question

I work with two application servers on a daily basis: one development, one production. A variety of apps from different developers live on these boxes, as well as some scrip

Answer 1

This came to my mind

if(filter_var(ini_get('display_errors'), FILTER_VALIDATE_BOOLEAN))
{
    // development
} 
else {
    // production
}

or a better approach

define('IN_DEVELOPEMENT', filter_var(ini_get('display_errors'), FILTER_VALIDATE_BOOLEAN));