I have a set-up where I have several (currently 2) computers actually
sharing /usr/share via an NFS mount. 

Furthermore I have tried to make this mount read-only.

Now I have the problem that when I build and install NetBSD software
on the NFS client machine, it'll try to install things into /usr/share.

Today I can avoid having manual pages installed by defining NOMAN in
/etc/mk.conf as they are already being installed by the NFS server
machine. But many programs want to install other things in other parts
of /usr/share than the manual pages.

Also it is not always sufficiently to say something along the line of

   cd /usr/src/bin
   make -k install

Besides generating error messages when trying to update /usr/share, this
also has the more serious consequence that if the /usr/share parts are
not the last parts being installed in each directory, some other parts of
the installation may be skipped that were not intended to be skipped.

As a consequence of this, I propose that the Makefiles be augmented with
a new variable (e.g. NOSHARE) that works like NOMAN: if it is present,
"make install" will skip those parts that go into /usr/share.

If this proposal is approved, I'm willing to produce specific proposals
for Makefile changes (both to /usr/share/mk and to specific makefiles)
and forward these proposals as PR's with patches for inclusion into the
source tree. As this may have consequences for quite a lot of Makefiles,
it may take quite some time before we get the all updated, but as I'm not
talking about changing the behaviour for those people who (by default)
don't use this new mechanism, I consider this acceptable.

regards
Erik Bertelsen