We should use the Makefile value of SHAREDIR when searching for config
files and templates etc.
This is important for systems which do not use the standard file
hierarchy or which do not have a consistent location for installing
program files, for example NixOS, which will have a different install
location with every update.
Signed-off-by: Daniel Patterson <me@danielpatterson.dev>
Acked-by: Robin Jarry <robin@jarry.cc>