This part adds the helper code to setup and tear down macvtap devices
using direct communication with the device driver via netlink sockets.
The rather short messages received from the netlink layer are now
written into a dynamically allocated buffer
* src/util/macvtap.h src/util/macvtap.c: provides the new module
* po/POTFILES.in: the module contains translated strings
This patch adds build support for libvirt checking for certain contents
of /usr/include/linux/if_link.h to see whether macvtap support is
compilable on that system. One can disable macvtap support in libvirt
via --without-macvtap passed to configure.
* configure.ac src/Makefile.am: new build support
* src/libvirt_macvtap.syms: list of exported symbols
* src/util/macvtap.c: empty module to not break compilation