Problem with 'make clean' in some ports

[walt]

While updating my gtk12 and gtk20 ports I noticed that in both
cases a 'make clean' failed with similar errors:
# make clean
cd: can't cd to &&
*** Error code 2
Stop in /opt/ports/x11-toolkits/gtk20.
*** Error code 1
On this machine /usr/ports is a symlink to /opt/ports and
/usr/dfports is a symlink to /opt/dfports for space reasons.
If I pick any other random port and do a 'make clean' it
works normally.
Can anyone else reproduce this?