Adding support for compiling against pppd-2.5.0 (or master branch)
- Updating configure.ac to support detecting pppd >= 2.5.0
- Fixing up nm-pppd-plugin.c
- Adding nm-pppd-compat.h to handle version differences
Note that pppd-2.5.0 isn't released yet, and there is still a few pending PRs left. If you find that there are something that needs to change, please find and report these issues to the pppd project as soon as possible.