Fix MinGW SDK redist: sdl2-config.cmake needs to set SDL2_FOUND

mingw/pkg-support/cmake/sdl2-config.cmake

@@ -6,13 +6,13 @@ if(CMAKE_SIZEOF_VOID_P EQUAL 4)
 elseif(CMAKE_SIZEOF_VOID_P EQUAL 8)
     set(sdl2_config_path "${CMAKE_CURRENT_LIST_DIR}/../x86_64-w64-mingw32/lib/cmake/SDL2/sdl2-config.cmake")
 else("${CMAKE_SIZEOF_VOID_P}" STREQUAL "")
-    set(PACKAGE_VERSION_UNSUITABLE TRUE)
+    set(SDL2_FOUND FALSE)
     return()
 endif()
 
 if(NOT EXISTS "${sdl2_config_path}")
     message(WARNING "${sdl2_config_path} does not exist: MinGW development package is corrupted")
-    set(PACKAGE_VERSION_UNSUITABLE TRUE)
+    set(SDL2_FOUND FALSE)
     return()
 endif()