Should fix Coverity CID-348 (dereference before NULL check).

gdi32: CreateBitmap and friends should return stock DEFAULT_BITMAP if requested bitmap width or height is 0.

credui: Fill out the username, password and domain edit boxes from the values input to CredUIPromptForCredentialsW.

Set the focus to the password edit box, unless the user edit box is empty.

winapi_check: Print a warning when 'long' is used in an API file as this type is not Win64 compatible.