fix Homebrew version of makefile.osx.patch

patching failed on master-0.8:

```
$ patch -p1 < contrib/homebrew/makefile.osx.patch
patching file src/makefile.osx
Hunk #2 FAILED at 35.
1 out of 2 hunks FAILED -- saving rejects to file src/makefile.osx.rej
```

This is a fix for that.