qemu buster backport

[Matt Taggart <taggart@debian.org>]

Hi qemu package maintainers!

Please consider providing a backport of newer qemu to buster.

In particular I would like to be able to use the added support for 
DISCARD in virtio-blk (added in 4.0). My VMs are running on top of 
drbd+lvm+luks+mdadm and all those layers of the stack have discard 
support in buster, so having newer qemu is the last piece needed to make 
it work.

I realize qemu is pretty complicated and depends on many lower level 
things, but hopefully this is possible.

Thanks,

--
Matt Taggart
taggart@debian.org