Only compile and run 'test_overload_callback' when compiling in WASAPI

This fixes #264.

CMakeLists.txt

@@ -193,10 +193,12 @@ target_include_directories(test_duplex PRIVATE ${gtest_SOURCE_DIR}/include)
 target_link_libraries(test_duplex PRIVATE cubeb gtest_main)
 add_test(duplex test_duplex)
 
+if (USE_WASAPI)
 add_executable(test_overload_callback test/test_overload_callback.cpp)
 target_include_directories(test_overload_callback PRIVATE ${gtest_SOURCE_DIR}/include)
 target_link_libraries(test_overload_callback PRIVATE cubeb gtest_main)
 add_test(overload_callback test_overload_callback)
+endif()
 
 add_executable(test_latency test/test_latency.cpp)
 target_include_directories(test_latency PRIVATE ${gtest_SOURCE_DIR}/include)