Fix slashes in BMI path for MSVC builds

Note that this is still broken when using -G Ninja

Author: tkhyn

CMakeLists.txt

@@ -27,7 +27,7 @@ endfunction()
 # DEPRECATED! Should be merged into add_module_library.
 function(enable_module target)
   if (MSVC)
-    set(BMI ${CMAKE_CURRENT_BINARY_DIR}/${target}.ifc)
+    file(TO_NATIVE_PATH "${CMAKE_CURRENT_BINARY_DIR}/${target}.ifc" BMI)
     target_compile_options(${target}
       PRIVATE /interface /ifcOutput ${BMI}
       INTERFACE /reference fmt=${BMI})