cmake: also add the recently-added include folder to the public interface

CMakeLists.txt

@@ -3076,6 +3076,7 @@ if(SDL_TEST)
   set_target_properties(SDL2_test PROPERTIES
       EXPORT_NAME SDL2test)
   target_include_directories(SDL2_test PUBLIC
+      "$<BUILD_INTERFACE:${SDL2_BINARY_DIR}/include-config-$<LOWER_CASE:$<CONFIG>>>"
       "$<BUILD_INTERFACE:${SDL2_SOURCE_DIR}/include>"
       $<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}> $<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}/SDL2>)
   target_link_libraries(SDL2_test PRIVATE ${EXTRA_TEST_LIBS})

test/CMakeLists.txt

@@ -6,10 +6,6 @@ if(SDL_INSTALL_TESTS)
     include(GNUInstallDirs)
 endif()
 
-# Global settings for all of the test targets
-# FIXME: is this wrong?
-remove_definitions(-DUSING_GENERATED_CONFIG_H)
-
 if(PSP)
     link_libraries(
         SDL2main