Many thanks reyalp. I just upgraded to 4.3.2 and everything now compiles!
My total lack of unix experience (after 25 years of PC DOS, OS/2 and Windows) meant it took me quite a time to upgrade. It turns out I needed to selfupgrade my macports first (it was downloading 4.1.0), deactivate the old arm-elf-gcc, install the latest version and then completely reset my PATH (which had lots of junk in it).
