<?=$var?>

Continuing in my effort to port an app from PHP version 5.1.6 to
5.3.3, the app uses this construct all over the place when building
links:

<?=$var?>

I never could find any documentation for this, but I assumed it was
some conditional thing - use $var if it's defined, otherwise use
nothing. In 5.1.6 it seems to do just that. But in 5.3.3 I'm not
getting the value of $var even when it is defined. Has this construct
been deprecated? Is there now some other way to achieve this?