I don't think SDL2 needs the DirectX SDK anymore.

readme.md

@@ -7,7 +7,6 @@ Prerequisites
 
  - Windows.
  - [Visual Studio 2013 (Express)][vs2013] preferably for desktop. VS 2015 and 2017 also work, but they have 40 more runtime DLLs distributed with love compared to VS 2013.
- - [DirectX SDK][dxsdk] required for SDL2. If you encounter **Error Code S1023** you may need to [uninstall some packages][s1023] and reinstall them after installing the DirectX SDK.
  - [CMake 3.1][cmake] or greater.
  - [NSIS][nsis] if you want to build the LÖVE installer.