Ran into this. Went away after I reinstalled geos, gdal, and libspatialite (relinking each as well). I can't say this is the recipe to copy/paste, but play with it and see if you can get it to work:
brew reinstall gdal
brew unlink gdal && brew link gdal
brew reinstall geos
brew unlink geos && brew link geos
brew reinstall libspatialite
brew unlink libspatialite && brew link libspatialite
You might have to do it in a different order, or redo one after the other in a way that gets the libraries in order. Don't uninstall postgis-2.0.x either, since you'll need the (both) libraries to soft-upgrade.