libcap vs libcap-ng mess

[Dr. David Alan Gilbert]

Hi,
  We seem to have a bit of a mess with libcap and libcap-ng; and I'm not
sure if we should try and untangle it.

a) Our configure script has tests for both libcap and libcap-ng
  for libcap it says $cap, for libcap-ng it says $cap_ng (ok)
  If $cap is set - nothing happens?
  If $cap_ng is set - we define CONFIG_LIBCAP  (!)

b) We use both
  1) pr-helper and bridge-helper use CONFIG_LIBCAP and use cap-ng
  2) 9p's virtfs-proxy-helper uses libcap - it's got a check in
     configure to make sure you have libcap if you've asked for 9p

c) Our gitlab-ci.yml installs libcap-dev to get the 9p stuff tested
  but never installes libcap-ng-dev

I hit this because we're using libcap in virtiofsd at the moment.

So hmm how to fix?
I'm tempted to:
  x) Replace CONFIG_LIBCAP by CONFIG_LIBCAPNG to make it clear
  y) Should we flip over to only using one or the other - what
     are the advantages?
  z) We should probably add the other one to the ci.

Dave

--
Dr. David Alan Gilbert / address@hidden / Manchester, UK