A quick note for anyone googling this particular problem:
Getting “cannot find code object on disk” when compiling with latest XCode with code signing turned on?
Hard to find the solution on the net, but eventually I figured it out – latest xcode does not have all the tools bundled yet. Do this:
ln -s /usr/bin/codesign_allocate /Applications/Xcode.app/Contents/Developer/usr/bin/codesign_allocate