PHP pass variable to include

I'm trying to pass a variable into an include file. My host changed PHP version and now whatever solution I try doesn't work.

I think I've tried every option I could find. I'm sure it's the simplest thing!

The variable needs to be set and evaluated from the calling first file (it's actually $_SERVER['PHP_SELF'], and needs to return the path of that file, not the included second.php).

OPTION ONE

In the first file:

global $variable;
$variable = "apple";
include('second.php');

In the second file:

echo $variable;

OPTION TWO

In the first file:

function passvariable(){
    $variable = "apple";
    return $variable;
}
passvariable();

OPTION THREE

$variable = "apple";
include "myfile.php?var=$variable"; // and I tried with http: and full site address too.


$variable = $_GET["var"]
echo $variable

None of these work for me. PHP version is 5.2.16.

What am I missing?

Thanks!