Accepted patch https://github.com/microsoft/vcpkg/blob/master/ports/sdl2/fix-space-in-path.patch

CMakeLists.txt

@@ -278,7 +278,7 @@ add_definitions(-DUSING_GENERATED_CONFIG_H)
 # General includes
 include_directories(${SDL2_BINARY_DIR}/include ${SDL2_SOURCE_DIR}/include)
 if(USE_GCC OR USE_CLANG)
-  set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -idirafter ${SDL2_SOURCE_DIR}/src/video/khronos")
+  set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -idirafter \"${SDL2_SOURCE_DIR}/src/video/khronos\"")
 else()
   include_directories(${SDL2_SOURCE_DIR}/src/video/khronos)
 endif()