diff --git a/Modules/CMakeAddFortranSubdirectory.cmake b/Modules/CMakeAddFortranSubdirectory.cmake
index 70e6a42443..b948af38df 100644
--- a/Modules/CMakeAddFortranSubdirectory.cmake
+++ b/Modules/CMakeAddFortranSubdirectory.cmake
@@ -237,6 +237,12 @@ function(cmake_add_fortran_subdirectory subdir)
         "${CMAKE_CURRENT_BINARY_DIR}/${${dir_var}}" ABSOLUTE)
     endif()
   endforeach()
+  # list the import libraries produced by the external project so that
+  # generators like Ninja know which rule creates them
+  set(byproducts)
+  foreach(lib IN LISTS libraries)
+    list(APPEND byproducts "${library_dir}/lib${lib}.lib")
+  endforeach()
   # create build and configure wrapper scripts
   _setup_mingw_config_and_build("${source_dir}" "${build_dir}")
   # create the external project
@@ -248,6 +254,7 @@ function(cmake_add_fortran_subdirectory subdir)
     BUILD_COMMAND ${CMAKE_COMMAND}
     -P ${build_dir}/build_mingw.cmake
     BUILD_ALWAYS 1
+    BUILD_BYPRODUCTS ${byproducts}
     INSTALL_COMMAND ""
     )
   # create imported targets for all libraries
diff --git a/Modules/CMakeAddFortranSubdirectory/build_mingw.cmake.in b/Modules/CMakeAddFortranSubdirectory/build_mingw.cmake.in
index 55b271a2d0..ee8bf0ec65 100644
--- a/Modules/CMakeAddFortranSubdirectory/build_mingw.cmake.in
+++ b/Modules/CMakeAddFortranSubdirectory/build_mingw.cmake.in
@@ -1,2 +1,11 @@
 set(ENV{PATH} "@MINGW_PATH@\;$ENV{PATH}")
-execute_process(COMMAND "@CMAKE_COMMAND@" --build . )
+# rebuild from scratch if a byproduct was removed, e.g. by a clean of
+# the outer project, because the inner build would consider itself up to date
+set(byproducts "@byproducts@")
+set(clean_first "")
+foreach(byproduct IN LISTS byproducts)
+  if(NOT EXISTS "${byproduct}")
+    set(clean_first --clean-first)
+  endif()
+endforeach()
+execute_process(COMMAND "@CMAKE_COMMAND@" --build . ${clean_first})