Try to fix Windows' multi-configuration behavior for LIBRARY_OUTPUT_D…

…IRECTORY

opensimcreator/CMakeLists.txt

@@ -17,7 +17,12 @@ target_link_libraries(opensimcreator_core PRIVATE OpenSimCreator)
 # make the output module directly build into the python package, so that
 # test suites, developers, etc. can directly start using it (e.g. via REPL)
 set_target_properties(opensimcreator_core PROPERTIES
-    LIBRARY_OUTPUT_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}/src/opensimcreator
+    # > Multi-configuration generators (Visual Studio, Xcode, Ninja Multi-Config) append
+    # > a per-configuration subdirectory to the specified directory ***unless a generator
+    # > expression is used***.
+    #     - https://cmake.org/cmake/help/latest/prop_tgt/LIBRARY_OUTPUT_DIRECTORY.html
+    LIBRARY_OUTPUT_DIRECTORY $<1:${CMAKE_CURRENT_SOURCE_DIR}>/src/opensimcreator/
+    RUNTIME_OUTPUT_DIRECTORY $<1:${CMAKE_CURRENT_SOURCE_DIR}>/src/opensimcreator/
 )
 
 if(BUILD_TESTING)