Replying to Colin: 
I've contacted the developer of atlex. He seems to agree with licensing the library as GPLv2+. Since it's the company repository, he waits for a "yes" from it's legal team.

Track the issue here: https://github.com/Amebis/atlex/issues/2

Alexander

2017-07-12 10:27 GMT+03:00 Alexander Sh. <chaez.san@gmail.com>:

Hello, I am sanchaez (Alexander Shaposhnikov) - a GSoC student working on RAPPS. I've found a set of useful wrappers for ATL on Github - https://github.com/Amebis/atlex.
I have some questions:

1. It is GPLv3. Is it compatible with ROS license? Can I use them?
2. If I can, where to place it in the source folders?

P.S. I've rushed a little by committing it to my branch. "It lies in reactos\sdk\include\reactos" for now.

Thanks in advance,
Alexander