Don't try building C++ tests when forcing C89.

CMakeLists.txt

@@ -583,14 +583,17 @@ if(MINIAUDIO_BUILD_TESTS)
         target_link_libraries(${name} PRIVATE miniaudio_common_options)
     endfunction()
 
+    # Disable C++ tests when forcing C89. This is needed because we'll be passing -std=c89 which will cause errors when trying to compile a C++ file.
+    if(NOT MINIAUDIO_FORCE_C89)
         # The debugging test is only used for debugging miniaudio itself. Don't do add_test() for this, and do not include it in in any automated testing.
         add_miniaudio_test(miniaudio_debugging debugging/debugging.cpp)
 
-    add_miniaudio_test(miniaudio_deviceio deviceio/deviceio.c)
-    add_test(NAME miniaudio_deviceio COMMAND miniaudio_deviceio --auto)
-
         add_miniaudio_test(miniaudio_cpp cpp/cpp.cpp)
         add_test(NAME miniaudio_cpp COMMAND miniaudio_cpp --auto) # This is just the deviceio test.
+    endif()
+
+    add_miniaudio_test(miniaudio_deviceio deviceio/deviceio.c)
+    add_test(NAME miniaudio_deviceio COMMAND miniaudio_deviceio --auto)
 
     add_miniaudio_test(miniaudio_conversion conversion/conversion.c)
     add_test(NAME miniaudio_conversion COMMAND miniaudio_conversion)