https://bugs.winehq.org/show_bug.cgi?id=12714
--- Comment #43 from winetest@luukku.com --- Since you got git environment there. You could do the following.
You could add FIXME("print this message"); and similar lines to the source code close to the point that the commit did changes.
git show commit
http://source.winehq.org/git/wine.git/blob/fa542355e97b943f6d58faf68e78c9b1c...
You would get better picture where exactly it fails.
Since the commit is so simple, would think that fixing it woulndt be so hard either.