Fix BMI path for MSVC builds when building with Ninja generator

CMakeLists.txt

@@ -27,7 +27,15 @@ endfunction()
 # DEPRECATED! Should be merged into add_module_library.
 function(enable_module target)
   if (MSVC)
-    file(TO_NATIVE_PATH "${CMAKE_CURRENT_BINARY_DIR}/${target}.ifc" BMI)
+    if (CMAKE_GENERATOR STREQUAL "Ninja")
+      file(RELATIVE_PATH FMT_REL_BIN_DIR ${CMAKE_BINARY_DIR} ${CMAKE_CURRENT_BINARY_DIR})
+      if (FMT_REL_BIN_DIR)
+        set(FMT_REL_BIN_DIR ${FMT_REL_BIN_DIR}/)
+      endif()
+      file(TO_NATIVE_PATH "${FMT_REL_BIN_DIR}CMakeFiles/fmt.dir/${target}.ifc" BMI)
+    else()
+      file(TO_NATIVE_PATH "${CMAKE_CURRENT_BINARY_DIR}/${target}.ifc" BMI)
+    endif()
     target_compile_options(${target}
       PRIVATE /interface /ifcOutput ${BMI}
       INTERFACE /reference fmt=${BMI})