DAHDI trunkdev is a newly-introduced 'virtual trunk' character device
which is used instead of a real hardware driver. This means that an
application (such as osmo-e1d) can implement a virtual E1 trunk and
receive and transmit E1 frame data which is exposed to DAHDI users
just like the data from a real physical E1 span.
In order to build DAHDI trunkdev support into osmo-e1d, you will need
a special fork of dahdi containing the required support, currently
the laforge/trunkdev branch of the following repository:
https://gitea.osmocom.org/retronetworking/dahdi-linux
Change-Id: Ib15a7313fcd63e1ed9f2f5b349df967bc4335ec2
