Compiler error trying to install Astropy

[shj.wallstrom@…]

I've been trying to install py27-astropy for days now but I get the following error: "Error: org.macports.build for port py27-astropy returned: command execution failed Please see the log file for port py27-astropy for details: /opt/local/var/macports/logs/_opt_local_var_macports_sources_rsync.macports.org_release_tarballs_ports_python_py-astropy/py27-astropy/main.log"

Checking this log file tells me (eventually): ":info:build Compiler specified by CC environment variable :info:build (/usr/bin/llvm-gcc-4.2:i686-apple-darwin11-llvm-gcc-4.2 (GCC) 4.2.1 (Based on Apple Inc. build 5658) (LLVM build 2336.1.00) :info:build Copyright (C) 2007 Free Software Foundation, Inc. :info:build This is free software; see the source for copying conditions. There is NO :info:build warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.) will fail to compile astropy. :info:build Please set CC=clang and try again. :info:build You can do this, for example, by running: :info:build :info:build CC=clang python setup.py <command> :info:build :info:build where <command> is the command you ran. :info:build :info:build Command failed: cd "/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_release_tarballs_ports_python_py-astropy/py27-astropy/work/astropy-1.0.4" && /opt/local/Library/Frameworks/Python.framework/Versions/2.7/bin/python2.7 setup.py --no-user-cfg --offline --no-git build --use-system-cfitsio --use-system-expat --use-system-wcslib --use-system-erfa "

from which I gather that the compiler clang is necessary. I did not appear to have this compiler, so I installed it via macports (clang-3.4), but still get the same error trying to install astropy. I cannot find any info about how to tell macports to use a different compiler here.