I compiled a non-universal version of 2.4-dev on my 10.7.2 system for the first time last night. I offer the following notes for the benefit of people who are inexperienced with UNIX/Darwin, compiling programs, etc. but are nonetheless brave enough to try following the "Non-universal binaries" instructions at
http://ufoai.ninex.info/wiki/index.php/Compile_for_Mac .
1. In Step 2, the text that starts "Edit the SDL_config.h..." can be ignored. You won't find the files or folders it speaks of, and the relevant file has been corrected already. Just cut and paste the 3 "sudo port" etc. commands into Terminal, press Return, and all will be well.
2. Before starting the "Compilation" section, you'll need to edit your .profile. This is because UFOAI compilation needs some paths that are not taken care of for you by the MacPorts installation process.
If you don't know what I'm talking about: (a) Download TextWrangler (freeware) from
http://www.barebones.com/products/textwrangler/download.html ; (b) Use its File > Open to navigate to your home folder and enable its "Show hidden files" option; and (c) Open the ".profile" file you should see now so you can edit it.
Toward the bottom, substitute this export command: export PATH=$PATH:/opt/local/bin:opt/local/sbin:opt/local
Save the file, quit Terminal, then relaunch Terminal to make the new PATH operative.
Now, the "make" commands should execute without errors. You should also be able to compile newer versions of UFOAI without editing .profile again, i.e., this is a one-time fix.