build break on windows

[fs-eire]

• Version: master
• Platform: Windows
• Subsystem:

Change fda2b9a introduced a build break in Windows ( without cygwin installed ).

'cp' is not recognized as an internal or external command

@ak239

[Hackzzila]

I had the same issue earlier, I just had to reinstall git and add the bash tools in the path. This is mentioned here.

[fs-eire]

I see... I thought UNIX tools are optional for building. (actually it is true before this commit)