Windows docker build warning non-windows docker host
From thaJeztah on GitHub:
That warning was added, because the Windows filesystem does not have an option to mark a file as 'executable'. Building a linux image from a Windows machine would therefore break the image if a file has to be marked executable.
For that reason, files are marked executable by default when building from a windows client; the warning is there so that you are notified of that, and (if needed), modify the Dockerfile to change/remove the executable bit afterwards.