This is an adaptation of bug #134517 filled against GConf, which requested this
same feature in that package and was already successfully fixed.

First, a bit of background: In pkgsrc (the native NetBSD's packaging system),
the user has the ability to configure the system-wide sysconfdir by defining a
variable, PKG_SYSCONFBASE, to where it should be.  Suppose he does:
 
        PKG_SYSCONFBASE=/etc/pkg

Then, all packages install their configuration files there, so gnopernicus ends
using /etc/pkg/gnopernicus-1.0 as its configuration directory (as pkgsrc gives
--sysconfdir=/etc/pkg to the configure script).  This is fine.

But this framework is more flexible.  It also allow users to specify the
configuration directory on a package basis.  So, that user could do:
 
        PKG_SYSCONFDIR.gnopernicus=/etc/foo/gnopernicus
 
And here comes the "problem".  Passing that value to gnopernicus' configure 
script (through the --sysconfdir argument) means that configuration files 
will end up in /etc/foo/gnopernicus/gnopernicus-1.0/*, as sources have hardcoded
in them the '/gnopernicus-1.0/' subdirectory.  Thus the user will get an
"unexpected" result.

In pkgsrc, we workaround this by patching gnopernicus' sources to remove that
part of the path on all accesses to the configuration directory.  But you
guessed right: this is error prone, and patches get out of sync on almost every
update.

My proposal is the following: remove the '/gnopernicus-1.0/' part from all paths 
that refer to the configuration directory, and keep it centralized somewhere
(that is, in the configure script).  This alone will make things more consistent 
(and in my oppinion, cleaner), as that part of the path won't be hardcoded in
the Makefile.am files.

And then, after changing this, allow the user to change the value of the
subdirectory.  This can be done through a configure argument, which is what the
attached patch does.  It provides the --with-sysconfsubdir argument that sets
the subdirectory under sysconfdir that will be used and modifies sources to
strip the '/gnopernicus-1.0/' part of paths.
 
Everything will behave as usual unless the user explicitly specifies this
option, so this is non-intrusive.