ok, take 3 on this.  after yesterday's changes, the problem still remains.
now the issue is that chk_path() is called (because the directory didn't
exist), but chk_path() sees that the whole path already exists (because
it was created in the meantime) and so it returns -1, which causes the
original node_creat() to fail.

it occurs to me that rather than continue to fuss with pax, it might be
better to avoid the problem by changing the makefiles to create the
$TOOLDIR/include/nbinclude stuff once (from tools/Makefile) rather than
3 times (from tools/{disklabel,fdisk,installboot}/Makefile including
tools/Makefile.disklabel).

which way do we want to go?

-Chuck