<bsd.own.mk> defines its own `install' target if none is defined,
which conflicts with the default one we define later on in bsd.port.mk.
This may nuke any WRKOBJDIR definitions (which I have yet to encounter),
but enables "make install" to work as expected.
+ Add temporary mtree file for any X11 packages (like xpm, jpeg etc),
which require a default X11 tree. This will change when we get a NetBSD
x11.dist mtree file.
+ Define SHAREOWN, SHAREGRP and SHAREMODE (in NetBSD) to be the same as
DOCOWN, DOCGRP and DOCMODE respectively.
0f091effee