make install: tar: could not chdir to '(null)'

[Gerald Pfeifer]

A few days ago, my FreeBSD 5.4-STABLE based tester (i386) started to fail 
in building packages, most notably lang/gcc40, lang/gcc41 and above.

  % make install
  ldconfig: /files/pfeifer/porttest/gcc40/lib/gcc-4.0.4: ignoring directory not owned by root
  ldconfig: mkstemp(/var/run/ld-elf.so.hints.iWE9fy): Permission denied
  % make package
  ===>  Building package for gcc-4.0.4,1
  tar: could not chdir to '(null)'

  pkg_create: make_dist: tar command failed with code 256
  Creating package /sw/test/FreeBSD/ports/pcvs/gcc40/gcc-4.0.4,1.tbz
  Registering depends: ldconfig_compat-1.0_8 libiconv-1.9.2_2.
  Creating bzip'd tar ball in '/sw/test/FreeBSD/ports/pcvs/gcc40/gcc-4.0.4,1.tbz'
  *** Error code 1

Has any of you ever seen anything like this?  This also affects ports
which test just fine on other machines (6-CURRENT, for example) and
have been testing fine on this machine.

I tried to track this down, but failed so far.  From what I can tell,
there have been no changes on this machines which might trigger this.

Gerald