dropfile: main callbacks need extra CMake care on UWP

test/CMakeLists.txt

@@ -273,7 +273,7 @@ add_sdl_test_executable(testrelative SOURCES testrelative.c)
 add_sdl_test_executable(testhittesting SOURCES testhittesting.c)
 add_sdl_test_executable(testdraw SOURCES testdraw.c)
 add_sdl_test_executable(testdrawchessboard SOURCES testdrawchessboard.c)
-add_sdl_test_executable(testdropfile SOURCES testdropfile.c)
+add_sdl_test_executable(testdropfile MAIN_CALLBACKS SOURCES testdropfile.c)
 add_sdl_test_executable(testerror NONINTERACTIVE SOURCES testerror.c)
 
 set(build_options_dependent_tests )