`make distclean` broke

I'm not sure when this started, but `make distclean` now ends with:

```
if test -d MacVim; then \
        xcodebuild -project MacVim/ clean; \
    fi
xcodebuild: error: 'MacVim/' is not a project file.
make[1]: *** [macvimclean] Error 66
make: *** [distclean] Error 2
```
