As I understand it, DirectXTK_Windows10.sln/.vcxproj is the UWP solution/project that should be built for DirectXTK -- however, the portfile does not differentiate and builds DirectXTK_Desktop_2017.sln for any triplet. That causes linker failures for dependent UWP projects.
Please note, that solution (DirectX_Windows10.sln) does not build the tools that are built under the Desktop solution. Thus the portfile would need to take that into account when installing MakeSpriteFont.exe XWBTool.exe.
As I understand it, DirectXTK_Windows10.sln/.vcxproj is the UWP solution/project that should be built for DirectXTK -- however, the portfile does not differentiate and builds DirectXTK_Desktop_2017.sln for any triplet. That causes linker failures for dependent UWP projects.
Please note, that solution (DirectX_Windows10.sln) does not build the tools that are built under the Desktop solution. Thus the portfile would need to take that into account when installing MakeSpriteFont.exe XWBTool.exe.