error: C preprocessor "/lib/cpp" fails sanity check with screen and git-core

[anno1604@…]

Hello, I have XCode Version 3.2.3

I have issues with git-core and the screen package, though I have an idea it's anything that requires building. I don't know what's going on, as everything was working fine and then suddenly not so much. I have been trying to install screen +vertical_split and git-core, and both fail with similar error logs. I have attached the screen output log as well as the config log. I have also attached the git-core ouput log. I have gcc installed, and have put a link to gcc: /lib/cpp (cpp -> /libexec/gcc/i686-apple-darwin10/4.0.1/cc1) like it's looking for however without any success. I have browsed around for answers but nothing has helped me so far.

Thank you

[anno1604@…]

Config Log output for screen package

[anno1604@…]

Ouput log for screen package

[anno1604@…]

Ouput log for git package

[ryandesign@…]

Reinstall Xcode, making sure the "UNIX Development" or "Command Line Support" option is selected.

[jmr@…]

No followup to Ryan's suggestions; assuming they worked.