disable utils that require dahdi pridump and pritest are utilities that we currently don't install. They require dahdi for building. They are not being installed. Let's not waste time on them.
If you need them installed, remove this patch and and install dahdi-source (dahdi/user.h) and libtonezone-dev (dahdi/tonezone.h).
Fix zero-size struct member usage These zero-members are not at the end of the struct, which is an old convention/extension to implement flexible member arrays. In this case it appears to be used as a replacement for unions.
Replace this kind of usage with actual unions, to preserve the ABI.
