Wordpress - Less And PHP - php

Question

I'm trying to figure out how to make a mixins.less file using PHP variables.
I made an Admin page and inside it I have colour selector. I want to use that colour inside my less files.
#colour: $mycolour;
I'm thinking to write a din_mixinds.less file using PHP and inside it to add the text;
And the to include the files in my style.less.
Or how can I do something better like this:
<?php
header("Content-type: text/css; charset: UTF-8");
$brandColor = "#990000";
$linkColor = "#555555";
$CDNURL = "http://cdn.blahblah.net";
?>
But with less not css.
Thank you
EDIT:
Based on Bass Jobsen answer.
Gives me an error:
<?php
header("Content-type: text/css; charset: UTF-8");
?>
body{
background-color: <?php echo 'red'; ?>;
}
Doesn't return any errors:
<?php
header("Content-type: text/css; charset: UTF-8");
?>
body{
background-color: red;
}

Answer 1

Well technical you can create a less.php file:
<?php
header("Content-type: text/css; charset: UTF-8");
$brandcolor = "#ff0099";
echo "#brandcolor: $brandcolor;";
And than serve that file on a URL (web server) and write in your Less code:
#import (less) url('http:/localhost/less.php');
p{
color: #brandcolor;
}
update
Yes ... I use less.php
I think that creates a different situation, with less.php you can use the following code to solve your issue:
$parser = new Less_Parser();
$parser->parseFile( 'style.less', 'http://example.com/mysite/' );
$parser->ModifyVars( array('brandcolor'=>'#ff00ff') );
$css = $parser->getCss();