We can extract the OSX 10.7 SDK from an XCode 4 DMG, but apple only provides Xcode 5 now. We will have to track down an old XCode 4.5 somehow. Here's the extraction scripts:
http://devernay.free.fr/hacks/xcodelegacy/
While I like phracker's style (aka "the baddest motherfucker"), the tarball version appears to be the newest version (for OSX 10.7.4 instead of 10.7.2 or earlier), and preserves mac property dotfiles.
Maybe too late now, but shouldn't the title of the commit be "Switch to OS X 10.7 SDK for ESR 38" rather than "Switch to ESR38 for OS X" ?
Yes, that would have been better. But in the end it does not matter that much as we want to squash all the changes to Tor Browser's .mozconfig files into one commit which could then have the commit message "Adding Tor Browser's .mozconfig files" or something.