imageantialias php5-gd problem

I am getting the following error that I believe tells me that GD Library is not working properly:

Fatal error: Call to undefined function imageantialias()...

php -r "var_dump( function_exists('imageantialias'));"
returns bool(false).

So the imageantialias does not exist.

I read somewhere in google that i have to recompile php5 by source.