Just in case anybody encounters this as well, I just had a build error while trying to build gwPython though MacPorts. It seems the OSX 10.6 SDK is missing some c++ headers or macports couldn’t find the headers located in /usr/include/c++/4.2.1/bits.
:info:build /Developer/SDKs/MacOSX10.6.sdk/usr/include/c++/4.2.1/exception:42:28: error: bits/c++config.h: No such file or directory
:info:build /Developer/SDKs/MacOSX10.6.sdk/usr/include/c++/4.2.1/iosfwd:45:29: error: bits/c++locale.h: No such file or directory
:info:build /Developer/SDKs/MacOSX10.6.sdk/usr/include/c++/4.2.1/iosfwd:46:25: error: bits/c++io.h: No such file or directory
A few google queries later, the solution seems to be to simply simlink the headers from /opt/local/include. I.e.
sudo ln -s /usr/include/c++/4.2.1/bits /opt/local/include/bits
After that, macports built gwPython just fine.