The problem appears to be a mismatch between workarounds that packages like
Python-MysqlDBdo to cope with where OS X puts include files and new places where such things are in
Xcode 4.4. In addition to installing the command line tools (from within the Xcode preferences (Downloads), my solution:
cd /System/Library/Frameworks/Python.framework/Versions/2.7/include su mv python2.7 python2.7.orig sudo ln -s \ /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.8.sdk/System/Library/Frameworks/Python.framework/Versions/2.7/include/python2.7 .
This could very well break a bunch of other stuff, but we'll see, it has my TiddlySpace dev environment working again.