v3: - add Piotr's patch from https://gitlab.winehq.org/wine/wine/-/merge_requests/5556 without which errno is not correctly tested in msvcr80/tests; - simplify some code bits (removed curlen loop as per Piotr's suggestion, unneeded break in the loop); - test errno thoroughly and fix it in implemetation; - set mv code page in test and test with that code page only; - add test for "all-zero" case and Piotr's diff handling of that.