how to add LD_PRELOAD in the xml

[Marc <Marc@xxxxxxxxxxxxxxxxx>]

How should I add LD_PRELOAD to domain xml. I guess within:

<qemu:commandline>
    <qemu:arg value='env=LD_PRELOAD=/usr/lib64/libtcmalloc.so'/>
</qemu:commandline>

but this is generating syntax errors.