source_group(TREE ...) crash with empty PREFIX
See the attached file for a minimum project reproducing the error with cmake 3.10.1:
go to build and run (in powershell): cmake .. -G"Visual Studio 15 Win64"
For me this results in all the normal stuff (check for compilers etc.) and then just dies without any projects or solution-files created. Putting something in the prefix makes it work. I was trying if I could force the files in the root folder to be be in the root folder in my project (alongside the cmakelists)