Fix for [#36819] *AFTER 2.69* Audio Only Sequencer wont render

The original description is not a bug, but the mixdown options were missing as scons was lacking the required defines during compile time.


git-svn-id: https://svn.blender.org/svnroot/bf-blender/trunk@61188 954f8c5b-7b00-dc11-b283-0030488c597c