exim won't install under MacPorts 1.8.0

[ndw@…]

Attempting to install exim under a clean MacPorts 1.8.0 install on Snow Leopard with the latest XCode fails:

$ sudo port install exim
--->  Computing dependencies for exim
--->  Fetching exim
--->  Verifying checksum(s) for exim
--->  Extracting exim
--->  Configuring exim
--->  Building exim
Error: Target org.macports.build returned: shell command " cd "/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_release_ports_mail_exim/work/exim-4.66" && /usr/bin/make -j2 all " returned error 2
Command output: /bin/sh: line 0: cd: build-Darwin-i386: No such file or directory
make[1]: Entering directory `/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_release_ports_mail_exim/work/exim-4.66'

>>> Creating links to source files...
mkdir: build-Darwin-i386: File exists
*** It appears that ../scripts/MakeLinks was previously interrupted.
*** You need to remove the build directory, and then run 'make' again.
make[1]: *** [build-directory] Error 1
make[1]: Leaving directory `/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_release_ports_mail_exim/work/exim-4.66'
make: *** [go] Error 2
make: *** Waiting for unfinished jobs....