In the previous release of KVM-72, native support for VDE was added but you needed to explicitly enable it during compilation using the –enabe-vde flag. Beginning with the latest release of KVM-73, native support for vde is enabled by default once vde libraries are detected on your system so there's no need to use the --enable-vde flag with your configure script. You can verify this during your configure run when compiling your kvm module. Below is an example of an output of running configure on a system with vde libraries installed.

Install prefix    /usr/local/kvm-73
BIOS directory    /usr/local/kvm-73/share/qemu
binary directory  /usr/local/kvm-73/bin
Manual directory  /usr/local/kvm-73/share/man
ELF interp prefix /usr/gnemul/qemu-%M
Source path       /root/Download/software/kvm-73/qemu
C compiler        gcc
Host C compiler   gcc
ARCH_CFLAGS       -m64
make              make
install           install
host CPU          x86_64
host big endian   no
target list       x86_64-softmmu
gprof enabled     no
profiler          no
static build      no
-Werror enabled   no
SDL support       yes
SDL static link   yes
curses support    no
mingw32 support   no
Audio drivers     oss
Extra audio cards 
Mixer emulation   no
VNC TLS support   no
kqemu support     no
kvm support       yes
CPU emulation     yes
brlapi support    no
Documentation     no
NPTL support      yes
vde support       yes
AIO support       yes

For procedure on how to compile and install vde libraries see the post here on building vde libraries.