--- a/ports/cmake/src/libout123/CMakeLists.txt
+++ b/ports/cmake/src/libout123/CMakeLists.txt
@@ -18,7 +18,7 @@ add_library(${TARGET}
     $<TARGET_OBJECTS:compat>
     $<$<BOOL:${USE_MODULES}>:$<TARGET_OBJECTS:compat_dl>>)
 
-set_target_properties(${TARGET} PROPERTIES OUTPUT_NAME out123)
+set_target_properties(${TARGET} PROPERTIES OUTPUT_NAME out123 WINDOWS_EXPORT_ALL_SYMBOLS ON)
 
 target_link_libraries(${TARGET} PRIVATE
     $<TARGET_NAME_IF_EXISTS:defaultmodule>
--- a/ports/cmake/src/libsyn123/CMakeLists.txt
+++ b/ports/cmake/src/libsyn123/CMakeLists.txt
@@ -15,7 +15,7 @@ add_library(${TARGET}
     "${CMAKE_CURRENT_SOURCE_DIR}/../../../../src/libsyn123/sampleconv.c"
     $<TARGET_OBJECTS:compat_str>)
 
-set_target_properties(${TARGET} PROPERTIES OUTPUT_NAME syn123)
+set_target_properties(${TARGET} PROPERTIES OUTPUT_NAME syn123 WINDOWS_EXPORT_ALL_SYMBOLS ON)
 
 target_include_directories(${TARGET} INTERFACE
     "$<BUILD_INTERFACE:${CMAKE_CURRENT_BINARY_DIR}>"