https://bugs.winehq.org/show_bug.cgi?id=41661
--- Comment #4 from Henri Verbeet hverbeet@gmail.com --- (In reply to Hugh McMaster from comment #3)
Sometimes .o files seem to be missed by .gitignore. But this is easily fixed by running 'git clean -f' from build root.
Are you sure those aren't from source files that have been removed since the .o was generated?